cc: Fix content size in R&R benchmark

This content size parameter is incorrectly small, which causes
additional clearing in some cases in the benchmark.

Bug: 810497
Cq-Include-Trybots: master.tryserver.blink:linux_trusty_blink_rel;master.tryserver.chromium.android:android_optional_gpu_tests_rel
Change-Id: I7a6bb361c29de6e5550f9f4b96becab08463bff5
Reviewed-on: https://chromium-review.googlesource.com/935147Reviewed-by: Khushal <khushalsagar@chromium.org>
Commit-Queue: enne <enne@chromium.org>
Cr-Commit-Position: refs/heads/master@{#538901}

cc/benchmarks/rasterize_and_record_benchmark_impl.cc

@@ -71,7 +71,8 @@ void RunBenchmark(RasterSource* raster_source,
       settings.image_provider = &image_provider;
 
       raster_source->PlaybackToCanvas(
-          &canvas, gfx::ColorSpace(), content_rect.size(), content_rect,
+          &canvas, gfx::ColorSpace(),
+          raster_source->GetContentSize(contents_scale), content_rect,
           content_rect, gfx::AxisTransform2d(contents_scale, gfx::Vector2dF()),
           settings);