Issue #1829 - Revert "Issue #1751"

dom/canvas/WebGLContext.h

@@ -30,6 +30,10 @@
 #include "ScopedGLHelpers.h"
 #include "TexUnpackBlob.h"
 
+#ifdef XP_MACOSX
+#include "ForceDiscreteGPUHelperCGL.h"
+#endif
+
 // Local
 #include "WebGLContextLossHandler.h"
 #include "WebGLContextUnchecked.h"
@@ -2011,6 +2015,15 @@ protected:
     JSObject* WebGLObjectAsJSObject(JSContext* cx, const WebGLObjectType*,
                                     ErrorResult& rv) const;
 
+#ifdef XP_MACOSX
+    // see bug 713305. This RAII helper guarantees that we're on the discrete GPU, during its lifetime
+    // Debouncing note: we don't want to switch GPUs too frequently, so try to not create and destroy
+    // these objects at high frequency. Having WebGLContext's hold one such object seems fine,
+    // because WebGLContext objects only go away during GC, which shouldn't happen too frequently.
+    // If in the future GC becomes much more frequent, we may have to revisit then (maybe use a timer).
+    ForceDiscreteGPUHelperCGL mForceDiscreteGPUHelper;
+#endif
+
 public:
     // console logging helpers
     void GenerateWarning(const char* fmt, ...);