Bug 1356218 - Fix nsDeviceContext::GetDepth to use the information from the correct monitor. r=jfkthame

MozReview-Commit-ID: BQpm6y3Ayo4

--HG--
extra : rebase_source : c798db446d28c0621d38fb65a5345300ace8cca7

gfx/src/nsDeviceContext.cpp

@@ -28,7 +28,6 @@
 #include "nsIObserver.h"                // for nsIObserver, etc
 #include "nsIObserverService.h"         // for nsIObserverService
 #include "nsIScreen.h"                  // for nsIScreen
-#include "nsIScreenManager.h"           // for nsIScreenManager
 #include "nsISupportsImpl.h"            // for MOZ_COUNT_CTOR, etc
 #include "nsISupportsUtils.h"           // for NS_ADDREF, NS_RELEASE
 #include "nsIWidget.h"                  // for nsIWidget, NS_NATIVE_WINDOW
@@ -38,10 +37,12 @@
 #include "nsTArray.h"                   // for nsTArray, nsTArray_Impl
 #include "nsThreadUtils.h"              // for NS_IsMainThread
 #include "mozilla/gfx/Logging.h"
+#include "mozilla/widget/ScreenManager.h" // for ScreenManager
 
 using namespace mozilla;
 using namespace mozilla::gfx;
 using mozilla::services::GetObserverService;
+using mozilla::widget::ScreenManager;
 
 class nsFontCache final : public nsIObserver
 {
@@ -190,7 +191,7 @@ nsFontCache::Flush()
 }
 
 nsDeviceContext::nsDeviceContext()
-    : mWidth(0), mHeight(0), mDepth(0),
+    : mWidth(0), mHeight(0),
       mAppUnitsPerDevPixel(-1), mAppUnitsPerDevPixelAtUnitFullZoom(-1),
       mAppUnitsPerPhysicalInch(-1),
       mFullZoom(1.0f), mPrintingScale(1.0f)
@@ -399,13 +400,15 @@ nsDeviceContext::CreateRenderingContextCommon(bool aWantReferenceContext)
 nsresult
 nsDeviceContext::GetDepth(uint32_t& aDepth)
 {
-    if (mDepth == 0 && mScreenManager) {
-        nsCOMPtr<nsIScreen> primaryScreen;
-        mScreenManager->GetPrimaryScreen(getter_AddRefs(primaryScreen));
-        primaryScreen->GetColorDepth(reinterpret_cast<int32_t *>(&mDepth));
+    nsCOMPtr<nsIScreen> screen;
+    FindScreen(getter_AddRefs(screen));
+    if (!screen) {
+        ScreenManager& screenManager = ScreenManager::GetSingleton();
+        screenManager.GetPrimaryScreen(getter_AddRefs(screen));
+        MOZ_ASSERT(screen);
     }
+    screen->GetColorDepth(reinterpret_cast<int32_t *>(&aDepth));
 
-    aDepth = mDepth;
     return NS_OK;
 }
 

gfx/src/nsDeviceContext.h

@@ -294,7 +294,6 @@ private:
 
     nscoord  mWidth;
     nscoord  mHeight;
-    uint32_t mDepth;
     int32_t  mAppUnitsPerDevPixel;
     int32_t  mAppUnitsPerDevPixelAtUnitFullZoom;
     int32_t  mAppUnitsPerPhysicalInch;