Bug 1096093 - Have Cocoa widget backend cache overlay scrollbar metrics. r=mstange.

--HG--
extra : rebase_source : fe44034cfbf4fe992a2adc56dc30864cc631cfa1

widget/cocoa/nsLookAndFeel.h

@@ -26,6 +26,10 @@ public:
 
   static bool UseOverlayScrollbars();
 
+  virtual nsTArray<LookAndFeelInt> GetIntCacheImpl();
+  virtual void SetIntCacheImpl(const nsTArray<LookAndFeelInt>& lookAndFeelIntCache);
+
+  virtual void RefreshImpl();
 protected:
 
   // Apple hasn't defined a constant for scollbars with two arrows on each end, so we'll use this one.
@@ -34,6 +38,13 @@ protected:
 
   static bool SystemWantsOverlayScrollbars();
   static bool AllowOverlayScrollbarsOverlap();
+
+private:
+  int32_t mUseOverlayScrollbars;
+  bool mUseOverlayScrollbarsCached;
+
+  int32_t mAllowOverlayScrollbarsOverlap;
+  bool mAllowOverlayScrollbarsOverlapCached;
 };
 
 #endif // nsLookAndFeel_h_

widget/cocoa/nsLookAndFeel.mm

@@ -12,6 +12,7 @@
 #include "gfxFont.h"
 #include "gfxFontConstants.h"
 #include "mozilla/gfx/2D.h"
+#include "mozilla/widget/WidgetMessageUtils.h"
 
 #import <Cocoa/Cocoa.h>
 
@@ -28,7 +29,12 @@ typedef NSInteger mozNSScrollerStyle;
 + (mozNSScrollerStyle)preferredScrollerStyle;
 @end
 
-nsLookAndFeel::nsLookAndFeel() : nsXPLookAndFeel()
+nsLookAndFeel::nsLookAndFeel()
+ : nsXPLookAndFeel()
+ , mUseOverlayScrollbars(-1)
+ , mUseOverlayScrollbarsCached(false)
+ , mAllowOverlayScrollbarsOverlap(-1)
+ , mAllowOverlayScrollbarsOverlapCached(false)
 {
 }
 
@@ -359,10 +365,18 @@ nsLookAndFeel::GetIntImpl(IntID aID, int32_t &aResult)
       aResult = eScrollThumbStyle_Proportional;
       break;
     case eIntID_UseOverlayScrollbars:
-      aResult = SystemWantsOverlayScrollbars() ? 1 : 0;
+      if (!mUseOverlayScrollbarsCached) {
+        mUseOverlayScrollbars = SystemWantsOverlayScrollbars() ? 1 : 0;
+        mUseOverlayScrollbarsCached = true;
+      }
+      aResult = mUseOverlayScrollbars;
       break;
     case eIntID_AllowOverlayScrollbarsOverlap:
-      aResult = AllowOverlayScrollbarsOverlap() ? 1 : 0;
+      if (!mAllowOverlayScrollbarsOverlapCached) {
+        mAllowOverlayScrollbarsOverlap = AllowOverlayScrollbarsOverlap() ? 1 : 0;
+        mAllowOverlayScrollbarsOverlapCached = true;
+      }
+      aResult = mAllowOverlayScrollbarsOverlap;
       break;
     case eIntID_ScrollbarDisplayOnMouseMove:
       aResult = 0;
@@ -633,3 +647,51 @@ nsLookAndFeel::GetFontImpl(FontID aID, nsString &aFontName,
 
     NS_OBJC_END_TRY_ABORT_BLOCK_RETURN(false);
 }
+
+nsTArray<LookAndFeelInt>
+nsLookAndFeel::GetIntCacheImpl()
+{
+  nsTArray<LookAndFeelInt> lookAndFeelIntCache =
+    nsXPLookAndFeel::GetIntCacheImpl();
+
+  LookAndFeelInt useOverlayScrollbars;
+  useOverlayScrollbars.id = eIntID_UseOverlayScrollbars;
+  useOverlayScrollbars.value = GetInt(eIntID_UseOverlayScrollbars);
+  lookAndFeelIntCache.AppendElement(useOverlayScrollbars);
+
+  LookAndFeelInt allowOverlayScrollbarsOverlap;
+  allowOverlayScrollbarsOverlap.id = eIntID_AllowOverlayScrollbarsOverlap;
+  allowOverlayScrollbarsOverlap.value = GetInt(eIntID_AllowOverlayScrollbarsOverlap);
+  lookAndFeelIntCache.AppendElement(allowOverlayScrollbarsOverlap);
+
+  return lookAndFeelIntCache;
+}
+
+void
+nsLookAndFeel::SetIntCacheImpl(const nsTArray<LookAndFeelInt>& lookAndFeelIntCache)
+{
+  for (auto entry : lookAndFeelIntCache) {
+    switch(entry.id) {
+      case eIntID_UseOverlayScrollbars:
+        mUseOverlayScrollbars = entry.value;
+        mUseOverlayScrollbarsCached = true;
+        break;
+      case eIntID_AllowOverlayScrollbarsOverlap:
+        mAllowOverlayScrollbarsOverlap = entry.value;
+        mAllowOverlayScrollbarsOverlapCached = true;
+        break;
+    }
+  }
+}
+
+void
+nsLookAndFeel::RefreshImpl()
+{
+  // We should only clear the cache if we're in the main browser process.
+  // Otherwise, we should wait for the parent to inform us of new values
+  // to cache via LookAndFeel::SetIntCache.
+  if (XRE_GetProcessType() == GeckoProcessType_Default) {
+    mUseOverlayScrollbarsCached = false;
+    mAllowOverlayScrollbarsOverlapCached = false;
+  }
+}