gecko-dev/widget/gonk/nsWindow.cpp

878 lines
22 KiB
C++

/* Copyright 2012 Mozilla Foundation and Mozilla contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "mozilla/DebugOnly.h"
#include <fcntl.h>
#include "android/log.h"
#include "mozilla/dom/TabParent.h"
#include "mozilla/Hal.h"
#include "mozilla/Preferences.h"
#include "mozilla/Services.h"
#include "mozilla/FileUtils.h"
#include "mozilla/ClearOnShutdown.h"
#include "gfxContext.h"
#include "gfxPlatform.h"
#include "gfxUtils.h"
#include "GLContextProvider.h"
#include "GLContext.h"
#include "nsAutoPtr.h"
#include "nsAppShell.h"
#include "nsIdleService.h"
#include "nsIObserverService.h"
#include "nsScreenManagerGonk.h"
#include "nsTArray.h"
#include "nsWindow.h"
#include "nsIWidgetListener.h"
#include "cutils/properties.h"
#include "ClientLayerManager.h"
#include "BasicLayers.h"
#include "libdisplay/GonkDisplay.h"
#include "pixelflinger/format.h"
#include "mozilla/BasicEvents.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/layers/APZCTreeManager.h"
#include "mozilla/layers/CompositorParent.h"
#include "ParentProcessController.h"
#include "nsThreadUtils.h"
#include "HwcComposer2D.h"
#define LOG(args...) __android_log_print(ANDROID_LOG_INFO, "Gonk" , ## args)
#define LOGW(args...) __android_log_print(ANDROID_LOG_WARN, "Gonk", ## args)
#define LOGE(args...) __android_log_print(ANDROID_LOG_ERROR, "Gonk", ## args)
#define IS_TOPLEVEL() (mWindowType == eWindowType_toplevel || mWindowType == eWindowType_dialog)
using namespace mozilla;
using namespace mozilla::dom;
using namespace mozilla::hal;
using namespace mozilla::gfx;
using namespace mozilla::gl;
using namespace mozilla::layers;
using namespace mozilla::widget;
nsIntRect gScreenBounds;
static uint32_t sScreenRotation;
static uint32_t sPhysicalScreenRotation;
static nsIntRect sVirtualBounds;
static nsTArray<nsWindow *> sTopWindows;
static nsWindow *gFocusedWindow = nullptr;
static bool sUsingHwc;
static bool sScreenInitialized;
namespace {
static uint32_t
EffectiveScreenRotation()
{
return (sScreenRotation + sPhysicalScreenRotation) % (360 / 90);
}
class ScreenOnOffEvent : public nsRunnable {
public:
ScreenOnOffEvent(bool on)
: mIsOn(on)
{}
NS_IMETHOD Run() {
for (uint32_t i = 0; i < sTopWindows.Length(); i++) {
nsWindow *win = sTopWindows[i];
if (nsIWidgetListener* listener = win->GetWidgetListener()) {
listener->SizeModeChanged(mIsOn ? nsSizeMode_Fullscreen : nsSizeMode_Minimized);
}
}
// Notify observers that the screen state has just changed.
nsCOMPtr<nsIObserverService> observerService = mozilla::services::GetObserverService();
if (observerService) {
observerService->NotifyObservers(
nullptr, "screen-state-changed",
mIsOn ? MOZ_UTF16("on") : MOZ_UTF16("off")
);
}
return NS_OK;
}
private:
bool mIsOn;
};
static StaticRefPtr<ScreenOnOffEvent> sScreenOnEvent;
static StaticRefPtr<ScreenOnOffEvent> sScreenOffEvent;
static void
displayEnabledCallback(bool enabled)
{
HwcComposer2D::GetInstance()->EnableVsync(enabled);
NS_DispatchToMainThread(enabled ? sScreenOnEvent : sScreenOffEvent);
}
} // anonymous namespace
nsWindow::nsWindow()
{
mFramebuffer = nullptr;
if (sScreenInitialized)
return;
sScreenOnEvent = new ScreenOnOffEvent(true);
ClearOnShutdown(&sScreenOnEvent);
sScreenOffEvent = new ScreenOnOffEvent(false);
ClearOnShutdown(&sScreenOffEvent);
GetGonkDisplay()->OnEnabled(displayEnabledCallback);
nsIntSize screenSize;
ANativeWindow *win = GetGonkDisplay()->GetNativeWindow();
if (win->query(win, NATIVE_WINDOW_WIDTH, &screenSize.width) ||
win->query(win, NATIVE_WINDOW_HEIGHT, &screenSize.height)) {
NS_RUNTIMEABORT("Failed to get native window size, aborting...");
}
gScreenBounds = nsIntRect(nsIntPoint(0, 0), screenSize);
char propValue[PROPERTY_VALUE_MAX];
property_get("ro.sf.hwrotation", propValue, "0");
sPhysicalScreenRotation = atoi(propValue) / 90;
sVirtualBounds = gScreenBounds;
sScreenInitialized = true;
nsAppShell::NotifyScreenInitialized();
// This is a hack to force initialization of the compositor
// resources, if we're going to use omtc.
//
// NB: GetPlatform() will create the gfxPlatform, which wants
// to know the color depth, which asks our native window.
// This has to happen after other init has finished.
gfxPlatform::GetPlatform();
if (!ShouldUseOffMainThreadCompositing()) {
MOZ_CRASH("How can we render apps, then?");
}
// Update sUsingHwc whenever layers.composer2d.enabled changes
Preferences::AddBoolVarCache(&sUsingHwc, "layers.composer2d.enabled");
}
nsWindow::~nsWindow()
{
HwcComposer2D::GetInstance()->SetCompositorParent(nullptr);
}
void
nsWindow::DoDraw(void)
{
if (!hal::GetScreenEnabled()) {
gDrawRequest = true;
return;
}
if (sTopWindows.IsEmpty()) {
LOG(" no window to draw, bailing");
return;
}
nsWindow *targetWindow = (nsWindow *)sTopWindows[0];
while (targetWindow->GetLastChild())
targetWindow = (nsWindow *)targetWindow->GetLastChild();
nsIWidgetListener* listener = targetWindow->GetWidgetListener();
if (listener) {
listener->WillPaintWindow(targetWindow);
}
LayerManager* lm = targetWindow->GetLayerManager();
if (mozilla::layers::LayersBackend::LAYERS_CLIENT == lm->GetBackendType()) {
// No need to do anything, the compositor will handle drawing
} else {
NS_RUNTIMEABORT("Unexpected layer manager type");
}
listener = targetWindow->GetWidgetListener();
if (listener) {
listener->DidPaintWindow();
}
}
nsEventStatus
nsWindow::DispatchInputEvent(WidgetGUIEvent& aEvent, bool* aWasCaptured)
{
if (aWasCaptured) {
*aWasCaptured = false;
}
if (!gFocusedWindow) {
return nsEventStatus_eIgnore;
}
gFocusedWindow->UserActivity();
aEvent.widget = gFocusedWindow;
if (TabParent* capturer = TabParent::GetEventCapturer()) {
bool captured = capturer->TryCapture(aEvent);
if (aWasCaptured) {
*aWasCaptured = captured;
}
if (captured) {
return nsEventStatus_eConsumeNoDefault;
}
}
nsEventStatus status;
gFocusedWindow->DispatchEvent(&aEvent, status);
return status;
}
NS_IMETHODIMP
nsWindow::Create(nsIWidget *aParent,
void *aNativeParent,
const nsIntRect &aRect,
nsDeviceContext *aContext,
nsWidgetInitData *aInitData)
{
BaseCreate(aParent, IS_TOPLEVEL() ? sVirtualBounds : aRect,
aContext, aInitData);
mBounds = aRect;
mParent = (nsWindow *)aParent;
mVisible = false;
if (!aParent) {
mBounds = sVirtualBounds;
}
if (!IS_TOPLEVEL())
return NS_OK;
sTopWindows.AppendElement(this);
Resize(0, 0, sVirtualBounds.width, sVirtualBounds.height, false);
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Destroy(void)
{
mOnDestroyCalled = true;
sTopWindows.RemoveElement(this);
if (this == gFocusedWindow)
gFocusedWindow = nullptr;
nsBaseWidget::OnDestroy();
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Show(bool aState)
{
if (mWindowType == eWindowType_invisible)
return NS_OK;
if (mVisible == aState)
return NS_OK;
mVisible = aState;
if (!IS_TOPLEVEL())
return mParent ? mParent->Show(aState) : NS_OK;
if (aState) {
BringToTop();
} else {
for (unsigned int i = 0; i < sTopWindows.Length(); i++) {
nsWindow *win = sTopWindows[i];
if (!win->mVisible)
continue;
win->BringToTop();
break;
}
}
return NS_OK;
}
bool
nsWindow::IsVisible() const
{
return mVisible;
}
NS_IMETHODIMP
nsWindow::ConstrainPosition(bool aAllowSlop,
int32_t *aX,
int32_t *aY)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Move(double aX,
double aY)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Resize(double aWidth,
double aHeight,
bool aRepaint)
{
return Resize(0, 0, aWidth, aHeight, aRepaint);
}
NS_IMETHODIMP
nsWindow::Resize(double aX,
double aY,
double aWidth,
double aHeight,
bool aRepaint)
{
mBounds = nsIntRect(NSToIntRound(aX), NSToIntRound(aY),
NSToIntRound(aWidth), NSToIntRound(aHeight));
if (mWidgetListener)
mWidgetListener->WindowResized(this, mBounds.width, mBounds.height);
if (aRepaint)
Invalidate(sVirtualBounds);
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Enable(bool aState)
{
return NS_OK;
}
bool
nsWindow::IsEnabled() const
{
return true;
}
NS_IMETHODIMP
nsWindow::SetFocus(bool aRaise)
{
if (aRaise)
BringToTop();
gFocusedWindow = this;
return NS_OK;
}
NS_IMETHODIMP
nsWindow::ConfigureChildren(const nsTArray<nsIWidget::Configuration>&)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::Invalidate(const nsIntRect &aRect)
{
nsWindow *top = mParent;
while (top && top->mParent)
top = top->mParent;
if (top != sTopWindows[0] && this != sTopWindows[0])
return NS_OK;
gDrawRequest = true;
mozilla::NotifyEvent();
return NS_OK;
}
nsIntPoint
nsWindow::WidgetToScreenOffset()
{
nsIntPoint p(0, 0);
nsWindow *w = this;
while (w && w->mParent) {
p.x += w->mBounds.x;
p.y += w->mBounds.y;
w = w->mParent;
}
return p;
}
void*
nsWindow::GetNativeData(uint32_t aDataType)
{
switch (aDataType) {
case NS_NATIVE_WINDOW:
return GetGonkDisplay()->GetNativeWindow();
}
return nullptr;
}
NS_IMETHODIMP
nsWindow::DispatchEvent(WidgetGUIEvent* aEvent, nsEventStatus& aStatus)
{
if (mWidgetListener)
aStatus = mWidgetListener->HandleEvent(aEvent, mUseAttachedEvents);
return NS_OK;
}
NS_IMETHODIMP_(void)
nsWindow::SetInputContext(const InputContext& aContext,
const InputContextAction& aAction)
{
mInputContext = aContext;
}
NS_IMETHODIMP_(InputContext)
nsWindow::GetInputContext()
{
// There is only one IME context on Gonk.
mInputContext.mNativeIMEContext = nullptr;
return mInputContext;
}
NS_IMETHODIMP
nsWindow::ReparentNativeWidget(nsIWidget* aNewParent)
{
return NS_OK;
}
NS_IMETHODIMP
nsWindow::MakeFullScreen(bool aFullScreen)
{
if (mWindowType != eWindowType_toplevel) {
// Ignore fullscreen request for non-toplevel windows.
NS_WARNING("MakeFullScreen() on a dialog or child widget?");
return nsBaseWidget::MakeFullScreen(aFullScreen);
}
if (aFullScreen) {
// Fullscreen is "sticky" for toplevel widgets on gonk: we
// must paint the entire screen, and should only have one
// toplevel widget, so it doesn't make sense to ever "exit"
// fullscreen. If we do, we can leave parts of the screen
// unpainted.
Resize(sVirtualBounds.x, sVirtualBounds.y,
sVirtualBounds.width, sVirtualBounds.height,
/*repaint*/true);
}
return NS_OK;
}
static gralloc_module_t const*
gralloc_module()
{
hw_module_t const *module;
if (hw_get_module(GRALLOC_HARDWARE_MODULE_ID, &module)) {
return nullptr;
}
return reinterpret_cast<gralloc_module_t const*>(module);
}
static SurfaceFormat
HalFormatToSurfaceFormat(int aHalFormat, int* bytepp)
{
switch (aHalFormat) {
case HAL_PIXEL_FORMAT_RGBA_8888:
*bytepp = 4;
return SurfaceFormat::R8G8B8A8;
case HAL_PIXEL_FORMAT_RGBX_8888:
*bytepp = 4;
return SurfaceFormat::R8G8B8X8;
case HAL_PIXEL_FORMAT_BGRA_8888:
*bytepp = 4;
return SurfaceFormat::B8G8R8A8;
case HAL_PIXEL_FORMAT_RGB_565:
*bytepp = 2;
return SurfaceFormat::R5G6B5;
default:
MOZ_CRASH("Unhandled HAL pixel format");
return SurfaceFormat::UNKNOWN; // not reached
}
}
TemporaryRef<DrawTarget>
nsWindow::StartRemoteDrawing()
{
GonkDisplay* display = GetGonkDisplay();
mFramebuffer = display->DequeueBuffer();
int width = mFramebuffer->width, height = mFramebuffer->height;
void *vaddr;
if (gralloc_module()->lock(gralloc_module(), mFramebuffer->handle,
GRALLOC_USAGE_SW_READ_NEVER |
GRALLOC_USAGE_SW_WRITE_OFTEN |
GRALLOC_USAGE_HW_FB,
0, 0, width, height, &vaddr)) {
EndRemoteDrawing();
return nullptr;
}
int bytepp;
SurfaceFormat format = HalFormatToSurfaceFormat(display->surfaceformat,
&bytepp);
return mFramebufferTarget = Factory::CreateDrawTargetForData(
BackendType::CAIRO, (uint8_t*)vaddr,
IntSize(width, height), mFramebuffer->stride * bytepp, format);
}
void
nsWindow::EndRemoteDrawing()
{
if (mFramebufferTarget) {
gralloc_module()->unlock(gralloc_module(), mFramebuffer->handle);
}
if (mFramebuffer) {
GetGonkDisplay()->QueueBuffer(mFramebuffer);
}
mFramebuffer = nullptr;
mFramebufferTarget = nullptr;
}
float
nsWindow::GetDPI()
{
return GetGonkDisplay()->xdpi;
}
double
nsWindow::GetDefaultScaleInternal()
{
float dpi = GetDPI();
// The mean pixel density for mdpi devices is 160dpi, 240dpi for hdpi,
// and 320dpi for xhdpi, respectively.
// We'll take the mid-value between these three numbers as the boundary.
if (dpi < 200.0) {
return 1.0; // mdpi devices.
}
if (dpi < 300.0) {
return 1.5; // hdpi devices.
}
// xhdpi devices and beyond.
return floor(dpi / 150.0 + 0.5);
}
LayerManager *
nsWindow::GetLayerManager(PLayerTransactionChild* aShadowManager,
LayersBackend aBackendHint,
LayerManagerPersistence aPersistence,
bool* aAllowRetaining)
{
if (aAllowRetaining)
*aAllowRetaining = true;
if (mLayerManager) {
// This layer manager might be used for painting outside of DoDraw(), so we need
// to set the correct rotation on it.
if (mLayerManager->GetBackendType() == LayersBackend::LAYERS_CLIENT) {
ClientLayerManager* manager =
static_cast<ClientLayerManager*>(mLayerManager.get());
manager->SetDefaultTargetConfiguration(mozilla::layers::BufferMode::BUFFER_NONE,
ScreenRotation(EffectiveScreenRotation()));
}
return mLayerManager;
}
// Set mUseLayersAcceleration here to make it consistent with
// nsBaseWidget::GetLayerManager
mUseLayersAcceleration = ComputeShouldAccelerate(mUseLayersAcceleration);
nsWindow *topWindow = sTopWindows[0];
if (!topWindow) {
LOGW(" -- no topwindow\n");
return nullptr;
}
CreateCompositor();
if (mCompositorParent) {
uint64_t rootLayerTreeId = mCompositorParent->RootLayerTreeId();
CompositorParent::SetControllerForLayerTree(rootLayerTreeId, new ParentProcessController());
CompositorParent::GetAPZCTreeManager(rootLayerTreeId)->SetDPI(GetDPI());
HwcComposer2D::GetInstance()->SetCompositorParent(mCompositorParent);
}
MOZ_ASSERT(mLayerManager);
return mLayerManager;
}
void
nsWindow::BringToTop()
{
if (!sTopWindows.IsEmpty()) {
if (nsIWidgetListener* listener = sTopWindows[0]->GetWidgetListener())
listener->WindowDeactivated();
}
sTopWindows.RemoveElement(this);
sTopWindows.InsertElementAt(0, this);
if (mWidgetListener)
mWidgetListener->WindowActivated();
Invalidate(sVirtualBounds);
}
void
nsWindow::UserActivity()
{
if (!mIdleService) {
mIdleService = do_GetService("@mozilla.org/widget/idleservice;1");
}
if (mIdleService) {
mIdleService->ResetIdleTimeOut(0);
}
}
uint32_t
nsWindow::GetGLFrameBufferFormat()
{
if (mLayerManager &&
mLayerManager->GetBackendType() == mozilla::layers::LayersBackend::LAYERS_OPENGL) {
// We directly map the hardware fb on Gonk. The hardware fb
// has RGB format.
return LOCAL_GL_RGB;
}
return LOCAL_GL_NONE;
}
nsIntRect
nsWindow::GetNaturalBounds()
{
return gScreenBounds;
}
bool
nsWindow::NeedsPaint()
{
if (!mLayerManager) {
return false;
}
return nsIWidget::NeedsPaint();
}
Composer2D*
nsWindow::GetComposer2D()
{
if (!sUsingHwc) {
return nullptr;
}
if (HwcComposer2D* hwc = HwcComposer2D::GetInstance()) {
return hwc->Initialized() ? hwc : nullptr;
}
return nullptr;
}
// nsScreenGonk.cpp
nsScreenGonk::nsScreenGonk(void *nativeScreen)
{
}
nsScreenGonk::~nsScreenGonk()
{
}
NS_IMETHODIMP
nsScreenGonk::GetId(uint32_t *outId)
{
*outId = 1;
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::GetRect(int32_t *outLeft, int32_t *outTop,
int32_t *outWidth, int32_t *outHeight)
{
*outLeft = sVirtualBounds.x;
*outTop = sVirtualBounds.y;
*outWidth = sVirtualBounds.width;
*outHeight = sVirtualBounds.height;
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::GetAvailRect(int32_t *outLeft, int32_t *outTop,
int32_t *outWidth, int32_t *outHeight)
{
return GetRect(outLeft, outTop, outWidth, outHeight);
}
static uint32_t
ColorDepth()
{
switch (GetGonkDisplay()->surfaceformat) {
case GGL_PIXEL_FORMAT_RGB_565:
return 16;
case GGL_PIXEL_FORMAT_RGBA_8888:
return 32;
}
return 24; // GGL_PIXEL_FORMAT_RGBX_8888
}
NS_IMETHODIMP
nsScreenGonk::GetPixelDepth(int32_t *aPixelDepth)
{
// XXX: this should actually return 32 when we're using 24-bit
// color, because we use RGBX.
*aPixelDepth = ColorDepth();
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::GetColorDepth(int32_t *aColorDepth)
{
return GetPixelDepth(aColorDepth);
}
NS_IMETHODIMP
nsScreenGonk::GetRotation(uint32_t* aRotation)
{
*aRotation = sScreenRotation;
return NS_OK;
}
NS_IMETHODIMP
nsScreenGonk::SetRotation(uint32_t aRotation)
{
if (!(aRotation <= ROTATION_270_DEG))
return NS_ERROR_ILLEGAL_VALUE;
if (sScreenRotation == aRotation)
return NS_OK;
sScreenRotation = aRotation;
uint32_t rotation = EffectiveScreenRotation();
if (rotation == nsIScreen::ROTATION_90_DEG ||
rotation == nsIScreen::ROTATION_270_DEG) {
sVirtualBounds = nsIntRect(0, 0, gScreenBounds.height,
gScreenBounds.width);
} else {
sVirtualBounds = gScreenBounds;
}
nsAppShell::NotifyScreenRotation();
for (unsigned int i = 0; i < sTopWindows.Length(); i++)
sTopWindows[i]->Resize(sVirtualBounds.width,
sVirtualBounds.height,
true);
return NS_OK;
}
// NB: This isn't gonk-specific, but gonk is the only widget backend
// that does this calculation itself, currently.
static ScreenOrientation
ComputeOrientation(uint32_t aRotation, const nsIntSize& aScreenSize)
{
bool naturallyPortrait = (aScreenSize.height > aScreenSize.width);
switch (aRotation) {
case nsIScreen::ROTATION_0_DEG:
return (naturallyPortrait ? eScreenOrientation_PortraitPrimary :
eScreenOrientation_LandscapePrimary);
case nsIScreen::ROTATION_90_DEG:
// Arbitrarily choosing 90deg to be primary "unnatural"
// rotation.
return (naturallyPortrait ? eScreenOrientation_LandscapePrimary :
eScreenOrientation_PortraitPrimary);
case nsIScreen::ROTATION_180_DEG:
return (naturallyPortrait ? eScreenOrientation_PortraitSecondary :
eScreenOrientation_LandscapeSecondary);
case nsIScreen::ROTATION_270_DEG:
return (naturallyPortrait ? eScreenOrientation_LandscapeSecondary :
eScreenOrientation_PortraitSecondary);
default:
MOZ_CRASH("Gonk screen must always have a known rotation");
}
}
/*static*/ uint32_t
nsScreenGonk::GetRotation()
{
return sScreenRotation;
}
/*static*/ ScreenConfiguration
nsScreenGonk::GetConfiguration()
{
ScreenOrientation orientation = ComputeOrientation(sScreenRotation,
gScreenBounds.Size());
uint32_t colorDepth = ColorDepth();
// NB: perpetuating colorDepth == pixelDepth illusion here, for
// consistency.
return ScreenConfiguration(sVirtualBounds, orientation,
colorDepth, colorDepth);
}
NS_IMPL_ISUPPORTS(nsScreenManagerGonk, nsIScreenManager)
nsScreenManagerGonk::nsScreenManagerGonk()
{
mOneScreen = new nsScreenGonk(nullptr);
}
nsScreenManagerGonk::~nsScreenManagerGonk()
{
}
NS_IMETHODIMP
nsScreenManagerGonk::GetPrimaryScreen(nsIScreen **outScreen)
{
NS_IF_ADDREF(*outScreen = mOneScreen.get());
return NS_OK;
}
NS_IMETHODIMP
nsScreenManagerGonk::ScreenForId(uint32_t aId,
nsIScreen **outScreen)
{
return GetPrimaryScreen(outScreen);
}
NS_IMETHODIMP
nsScreenManagerGonk::ScreenForRect(int32_t inLeft,
int32_t inTop,
int32_t inWidth,
int32_t inHeight,
nsIScreen **outScreen)
{
return GetPrimaryScreen(outScreen);
}
NS_IMETHODIMP
nsScreenManagerGonk::ScreenForNativeWidget(void *aWidget, nsIScreen **outScreen)
{
return GetPrimaryScreen(outScreen);
}
NS_IMETHODIMP
nsScreenManagerGonk::GetNumberOfScreens(uint32_t *aNumberOfScreens)
{
*aNumberOfScreens = 1;
return NS_OK;
}
NS_IMETHODIMP
nsScreenManagerGonk::GetSystemDefaultScale(float *aDefaultScale)
{
*aDefaultScale = 1.0f;
return NS_OK;
}