Remove old APIs for copyTextureCHROMIUM(...) and copyVideoTextureToPlatformTexture(...).

public/platform/WebGraphicsContext3D.h

Index: public/platform/WebGraphicsContext3D.h
diff --git a/public/platform/WebGraphicsContext3D.h b/public/platform/WebGraphicsContext3D.h
index 56a4c8a1157b577907573f5e5a6acfff7ed45237..8118fc749f69e49f63c4a4bf1b896c853d6d3771 100644
--- a/public/platform/WebGraphicsContext3D.h
+++ b/public/platform/WebGraphicsContext3D.h
@@ -452,11 +452,6 @@ public:
 
     // GL_CHROMIUM_copy_texture
     virtual void copyTextureCHROMIUM(WGC3Denum target, WGC3Duint sourceId,
-                                     WGC3Duint destId, WGC3Dint level, WGC3Denum internalFormat) { }
-    // This function adds one more parameter(destType) than the above one to define the destination texture if needed.
-    // TODO(jun.a.jiang@intel.com): once all clients switch to call this newer function with six parameters, the older
-    // one with five parameters would be removed.
-    virtual void copyTextureCHROMIUM(WGC3Denum target, WGC3Duint sourceId,
         WGC3Duint destId, WGC3Dint level, WGC3Denum internalFormat, WGC3Denum destType) { }
 
     // GL_CHROMIUM_shallow_flush