Fix UpdateTilePriorities viewport in Android WebView.

cc/output/gl_renderer_unittest.cc

Index: cc/output/gl_renderer_unittest.cc
diff --git a/cc/output/gl_renderer_unittest.cc b/cc/output/gl_renderer_unittest.cc
index c12bbfe3c0e93e331984dde7f644635e3aecc82a..0e153c1ce9a97d6839518deb2f1b1ceff0bb53aa 100644
--- a/cc/output/gl_renderer_unittest.cc
+++ b/cc/output/gl_renderer_unittest.cc
@@ -158,6 +158,9 @@ class FakeRendererClient : public RendererClient {
     static gfx::Size fake_size(1, 1);
     return gfx::Rect(fake_size);
   }
+  virtual gfx::Rect DeviceClip() const OVERRIDE {
+    return DeviceViewport();
+  }
   virtual float DeviceScaleFactor() const OVERRIDE {
     return scale_factor_;
   }