Raster PictureLayerTiling with fractional translation

cc/raster/gpu_raster_buffer_provider.cc

Index: cc/raster/gpu_raster_buffer_provider.cc
diff --git a/cc/raster/gpu_raster_buffer_provider.cc b/cc/raster/gpu_raster_buffer_provider.cc
index 85a77c201b3e62858684bcaae2729df63f4e35dd..841158fbbcc2dfeb078695c50af0bc0e1def708e 100644
--- a/cc/raster/gpu_raster_buffer_provider.cc
+++ b/cc/raster/gpu_raster_buffer_provider.cc
@@ -13,6 +13,7 @@
 #include "base/metrics/histogram_macros.h"
 #include "base/trace_event/trace_event.h"
 #include "cc/base/histograms.h"
+#include "cc/base/scale_translate2d.h"
 #include "cc/playback/image_hijack_canvas.h"
 #include "cc/playback/raster_source.h"
 #include "cc/raster/scoped_gpu_raster.h"
@@ -32,7 +33,7 @@ static sk_sp<SkPicture> PlaybackToPicture(
     const gfx::Size& resource_size,
     const gfx::Rect& raster_full_rect,
     const gfx::Rect& raster_dirty_rect,
-    float scale,
+    const ScaleTranslate2d& transform,
     const RasterSource::PlaybackSettings& playback_settings) {
   // GPU raster doesn't do low res tiles, so should always include images.
   DCHECK(!playback_settings.skip_images);
@@ -63,6 +64,9 @@ static sk_sp<SkPicture> PlaybackToPicture(
   sk_sp<SkCanvas> canvas = sk_ref_sp(
       recorder.beginRecording(resource_size.width(), resource_size.height()));
   canvas->save();
+  canvas->translate(-raster_full_rect.x(), -raster_full_rect.y());
+  canvas->clipRect(gfx::RectToSkRect(playback_rect));
+  transform.ApplyToCanvas(canvas.get());
 
   // The GPU image decode controller assumes that Skia is done with an image
   // when playback is complete. However, in this case, where we play back to a
@@ -74,7 +78,7 @@ static sk_sp<SkPicture> PlaybackToPicture(
   RasterSource::PlaybackSettings settings = playback_settings;
   settings.use_image_hijack_canvas = false;
   raster_source->PlaybackToCanvas(canvas.get(), raster_full_rect, playback_rect,
-                                  scale, settings);
+                                  transform, settings);
   canvas->restore();
   return recorder.finishRecordingAsPicture();
 }
@@ -146,13 +150,13 @@ void GpuRasterBufferProvider::RasterBufferImpl::Playback(
     const gfx::Rect& raster_full_rect,
     const gfx::Rect& raster_dirty_rect,
     uint64_t new_content_id,
-    float scale,
+    const ScaleTranslate2d& transform,
     const RasterSource::PlaybackSettings& playback_settings) {
   TRACE_EVENT0("cc", "GpuRasterBuffer::Playback");
   client_->PlaybackOnWorkerThread(&lock_, sync_token_,
                                   resource_has_previous_content_, raster_source,
                                   raster_full_rect, raster_dirty_rect,
-                                  new_content_id, scale, playback_settings);
+                                  new_content_id, transform, playback_settings);
 }
 
 GpuRasterBufferProvider::GpuRasterBufferProvider(
@@ -244,7 +248,7 @@ void GpuRasterBufferProvider::PlaybackOnWorkerThread(
     const gfx::Rect& raster_full_rect,
     const gfx::Rect& raster_dirty_rect,
     uint64_t new_content_id,
-    float scale,
+    const ScaleTranslate2d& transform,
     const RasterSource::PlaybackSettings& playback_settings) {
   ContextProvider::ScopedContextLock scoped_context(worker_context_provider_);
   gpu::gles2::GLES2Interface* gl = scoped_context.ContextGL();
@@ -261,7 +265,7 @@ void GpuRasterBufferProvider::PlaybackOnWorkerThread(
 
   sk_sp<SkPicture> picture = PlaybackToPicture(
       raster_source, resource_has_previous_content, resource_lock->size(),
-      raster_full_rect, raster_dirty_rect, scale, playback_settings);
+      raster_full_rect, raster_dirty_rect, transform, playback_settings);
 
   // Turn on distance fields for layers that have ever animated.
   bool use_distance_field_text =