Make Android StreamTexture implement GLStreamTextureImage

gpu/command_buffer/service/gl_stream_texture_image.h

Index: gpu/command_buffer/service/gl_stream_texture_image.h
diff --git a/gpu/command_buffer/service/gl_stream_texture_image.h b/gpu/command_buffer/service/gl_stream_texture_image.h
index a6a517de550a8db56825183a35e04419a218fe94..b5bc370c5ba58af945a348050c9229c9f7fc5b40 100644
--- a/gpu/command_buffer/service/gl_stream_texture_image.h
+++ b/gpu/command_buffer/service/gl_stream_texture_image.h
@@ -19,8 +19,18 @@ class GPU_EXPORT GLStreamTextureImage : public gl::GLImage {
 
   // Get the matrix.
   // Copy the texture matrix for this image into |matrix|.
+  // Subclasses must return a matrix appropriate for a coordinate system where
+  // UV=(0,0) corresponds to the bottom left corner of the image.
   virtual void GetTextureMatrix(float matrix[16]) = 0;
 
+  // Copy the texture matrix for this image into |matrix|, returning a matrix
+  // for which UV=(0,0) corresponds to the top left of corner of the image,
+  // which is what Chromium generally expects.
+  void GetFlippedTextureMatrix(float matrix[16]) {
+    GetTextureMatrix(matrix);
+    matrix[13] += matrix[5];
+    matrix[5] = -matrix[5];
+  }
  protected:
   ~GLStreamTextureImage() override {}