Implement support for origin-TopLeft render targets. Note that the default behaviour remains the same:  textures default to origin-TopLeft, render targets default to origin-BottomLeft, and backend textures default to origin-BottomLeft. However, the caller can override the default by setting fOrigin in GrTextureDesc, GrBackendTextureDesc or GrBackendRenderTargetDesc.

Review URL: https://codereview.appspot.com/7230049

git-svn-id: http://skia.googlecode.com/svn/trunk@7594 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/src/gpu/gl/GrGLRenderTarget.h b/src/gpu/gl/GrGLRenderTarget.h
index 9a39ca1..ea6ae87 100644
--- a/src/gpu/gl/GrGLRenderTarget.h
+++ b/src/gpu/gl/GrGLRenderTarget.h
@@ -25,12 +25,13 @@
     enum { kUnresolvableFBOID = 0 };
 
     struct Desc {
-        GrGLuint      fRTFBOID;
-        GrGLuint      fTexFBOID;
-        GrGLuint      fMSColorRenderbufferID;
-        bool          fIsWrapped;
-        GrPixelConfig fConfig;
-        int           fSampleCnt;
+        GrGLuint         fRTFBOID;
+        GrGLuint         fTexFBOID;
+        GrGLuint         fMSColorRenderbufferID;
+        bool             fIsWrapped;
+        GrPixelConfig    fConfig;
+        int              fSampleCnt;
+        GrSurfaceOrigin  fOrigin;
     };
 
     // creates a GrGLRenderTarget associated with a texture