From 4ac30461dd244d016038f9d4ba54106ace9212bc Mon Sep 17 00:00:00 2001
From: David Anderson <danderson@mozilla.com>
Date: Mon, 13 Jul 2015 01:12:26 -0700
Subject: [PATCH] Add an nsIGfxInfo function to query monitors. (bug 1175005
 part 1, r=mattwoodrow)

---
 widget/GfxInfoBase.cpp | 14 ++++++++++++++
 widget/GfxInfoBase.h   |  3 ++-
 widget/nsIGfxInfo.idl  | 13 ++++++++++++-
 3 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/widget/GfxInfoBase.cpp b/widget/GfxInfoBase.cpp
index 8625ba228a68..cf3e28b95709 100644
--- a/widget/GfxInfoBase.cpp
+++ b/widget/GfxInfoBase.cpp
@@ -1163,6 +1163,20 @@ GfxInfoBase::RemoveCollector(GfxInfoCollectorBase* collector)
   }
 }
 
+NS_IMETHODIMP
+GfxInfoBase::GetMonitors(JSContext* aCx, JS::MutableHandleValue aResult)
+{
+  JS::Rooted<JSObject*> array(aCx, JS_NewArrayObject(aCx, 0));
+
+  nsresult rv = FindMonitors(aCx, array);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+
+  aResult.setObject(*array);
+  return NS_OK;
+}
+
 GfxInfoCollectorBase::GfxInfoCollectorBase()
 {
   GfxInfoBase::AddCollector(this);
diff --git a/widget/GfxInfoBase.h b/widget/GfxInfoBase.h
index 6b539f234dce..2a87e19c31d4 100644
--- a/widget/GfxInfoBase.h
+++ b/widget/GfxInfoBase.h
@@ -54,7 +54,8 @@ public:
   NS_IMETHOD GetFeatureSuggestedDriverVersion(int32_t aFeature, nsAString & _retval) override;
   NS_IMETHOD GetWebGLParameter(const nsAString & aParam, nsAString & _retval) override;
 
-    NS_IMETHOD GetFailures(uint32_t *failureCount, int32_t** indices, char ***failures) override;
+  NS_IMETHOD GetMonitors(JSContext* cx, JS::MutableHandleValue _retval) override;
+  NS_IMETHOD GetFailures(uint32_t *failureCount, int32_t** indices, char ***failures) override;
   NS_IMETHOD_(void) LogFailure(const nsACString &failure) override;
   NS_IMETHOD GetInfo(JSContext*, JS::MutableHandle<JS::Value>) override;
 
diff --git a/widget/nsIGfxInfo.idl b/widget/nsIGfxInfo.idl
index fde9e6b27ff5..8b10556b2fa7 100644
--- a/widget/nsIGfxInfo.idl
+++ b/widget/nsIGfxInfo.idl
@@ -8,7 +8,7 @@
 
 /* NOTE: this interface is completely undesigned, not stable and likely to change */
 
-[scriptable, uuid(b0cd9d34-8dba-4b1d-8126-ca21826dbf35)]
+[scriptable, uuid(47eedfa0-f7cb-445b-b5cf-a2ca83600560)]
 interface nsIGfxInfo : nsISupports
 {
   /*
@@ -54,6 +54,17 @@ interface nsIGfxInfo : nsISupports
 
   readonly attribute boolean isGPU2Active;
 
+  /**
+   * Returns an array of objects describing each monitor. Guaranteed properties
+   * are "screenWidth" and "screenHeight". This is only implemented on Desktop.
+   *
+   * Windows additionally supplies "refreshRate" and "pseudoDisplay".
+   *
+   * OS X additionally supplies "scale".
+   */
+  [implicit_jscontext]
+  jsval getMonitors();
+
   void getFailures(
                out unsigned long failureCount,
                [optional, array, size_is(failureCount)] out long indices,