Add hooks for GL_EXT_debug_marker in gpu

src/gpu/GrGpu.h

Index: src/gpu/GrGpu.h
diff --git a/src/gpu/GrGpu.h b/src/gpu/GrGpu.h
index 00791be054a1e55ceb7c1c36c15c2a465677c7b9..35b53339db63d190a05435859e60c98cee0cb517 100644
--- a/src/gpu/GrGpu.h
+++ b/src/gpu/GrGpu.h
@@ -330,6 +330,11 @@ public:
 
     void getPathStencilSettingsForFillType(SkPath::FillType fill, GrStencilSettings* outStencilSettings);
 
+    // GrDrawTarget Overrides
+    virtual void insertEventMarker(const char* marker) SK_OVERRIDE;
+    virtual void pushGroupMarker(const char* marker) SK_OVERRIDE;
+    virtual void popGroupMarker() SK_OVERRIDE;
+
 protected:
     enum DrawType {
         kDrawPoints_DrawType,
@@ -458,6 +463,11 @@ private:
     // overridden by backend-specific derived class to perform the resolve
     virtual void onResolveRenderTarget(GrRenderTarget* target) = 0;
 
+    // overridden by backend-specific derived class to perform debug markers

[bsalomon, 2014/02/20 22:14:13]

I'd bubble the foo/onFoo split up to GrDT. We can have asserts, filters, etc
that get applied for all GrDT subclasses. And at that level we don't need a
double virtual call, the public ones can be non-virtual.

+    virtual void onInsertEventMarker(const char* marker) = 0;
+    virtual void onPushGroupMarker(const char* marker) = 0;
+    virtual void onPopGroupMarker() = 0;
+
     // width and height may be larger than rt (if underlying API allows it).
     // Should attach the SB to the RT. Returns false if compatible sb could
     // not be created.