cc: Re-enable disabled tile manager unittests (plus fixes)

cc/test/fake_display_list_raster_source.h

Index: cc/test/fake_display_list_raster_source.h
diff --git a/cc/test/fake_display_list_raster_source.h b/cc/test/fake_display_list_raster_source.h
index 4dcbfa9ef3ff43ad1f08d3cf32be35e135aefd68..d35775f70ce47c40c97102b3205fb36855fbff5e 100644
--- a/cc/test/fake_display_list_raster_source.h
+++ b/cc/test/fake_display_list_raster_source.h
@@ -43,6 +43,12 @@ class FakeDisplayListRasterSource : public DisplayListRasterSource {
                         const gfx::Rect& canvas_bitmap_rect,
                         const gfx::Rect& canvas_playback_rect,
                         float contents_scale) const override;
+  bool IsSolidColor() const override;
+
+  void set_is_solid_color(bool is_solid) {
+    is_solid_color_ = is_solid;
+    is_solid_color_overridden_ = true;
+  }
 
  protected:
   FakeDisplayListRasterSource(
@@ -55,6 +61,8 @@ class FakeDisplayListRasterSource : public DisplayListRasterSource {
   ~FakeDisplayListRasterSource() override;
 
  private:
+  bool is_solid_color_;
+  bool is_solid_color_overridden_;
   base::WaitableEvent* playback_allowed_event_;
 };