Surface Syncrhonization: Move HasAlwaysUpdateMetadataChanged out of RenderFrameMetadata

In a subsequent patch, the decision whether to ship a RenderFrameMetadata
to the browser process depends on on the scroll position relative to the edge
of the root layer. This complexity doesn't really belong in
cc::RenderFrameMetadata itself but rather its consumer. This CL moves the
code of whether to ship a RenderFrameMetadata out of the struct itself.

Bug: 672962
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;master.tryserver.blink:linux_trusty_blink_rel
Change-Id: I59b001088d3d83df7bd0dc9fe569e439af3fdeb9
Reviewed-on: https://chromium-review.googlesource.com/1115348Reviewed-by: Antoine Labour <piman@chromium.org>
Commit-Queue: Fady Samuel <fsamuel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570478}

cc/trees/render_frame_metadata.cc

@@ -17,32 +17,6 @@ RenderFrameMetadata::RenderFrameMetadata(RenderFrameMetadata&& other) = default;
 
 RenderFrameMetadata::~RenderFrameMetadata() {}
 
-// static
-bool RenderFrameMetadata::HasAlwaysUpdateMetadataChanged(
-    const RenderFrameMetadata& rfm1,
-    const RenderFrameMetadata& rfm2) {
-  return rfm1.root_background_color != rfm2.root_background_color ||
-         rfm1.is_scroll_offset_at_top != rfm2.is_scroll_offset_at_top ||
-         rfm1.selection != rfm2.selection ||
-         rfm1.page_scale_factor != rfm2.page_scale_factor ||
-#if defined(OS_ANDROID)
-         rfm1.top_controls_height != rfm2.top_controls_height ||
-         rfm1.top_controls_shown_ratio != rfm2.top_controls_shown_ratio ||
-         rfm1.bottom_controls_height != rfm2.bottom_controls_height ||
-         rfm1.bottom_controls_shown_ratio != rfm2.bottom_controls_shown_ratio ||
-         rfm1.min_page_scale_factor != rfm2.min_page_scale_factor ||
-         rfm1.max_page_scale_factor != rfm2.max_page_scale_factor ||
-         rfm1.root_overflow_y_hidden != rfm2.root_overflow_y_hidden ||
-         rfm1.scrollable_viewport_size != rfm2.scrollable_viewport_size ||
-         rfm1.root_layer_size != rfm2.root_layer_size ||
-         rfm1.has_transparent_background != rfm2.has_transparent_background ||
-#endif
-         rfm1.is_mobile_optimized != rfm2.is_mobile_optimized ||
-         rfm1.device_scale_factor != rfm2.device_scale_factor ||
-         rfm1.viewport_size_in_pixels != rfm2.viewport_size_in_pixels ||
-         rfm1.local_surface_id != rfm2.local_surface_id;
-}
-
 RenderFrameMetadata& RenderFrameMetadata::operator=(
     const RenderFrameMetadata&) = default;
 

cc/trees/render_frame_metadata.h

@@ -25,12 +25,6 @@ class CC_EXPORT RenderFrameMetadata {
   RenderFrameMetadata(RenderFrameMetadata&& other);
   ~RenderFrameMetadata();
 
-  // Certain fields should always have their changes reported. This will return
-  // true when there is a difference between |rfm1| and |rfm2| for those fields.
-  // These fields have a low frequency rate of change.
-  static bool HasAlwaysUpdateMetadataChanged(const RenderFrameMetadata& rfm1,
-                                             const RenderFrameMetadata& rfm2);
-
   RenderFrameMetadata& operator=(const RenderFrameMetadata&);
   RenderFrameMetadata& operator=(RenderFrameMetadata&& other);
   bool operator==(const RenderFrameMetadata& other) const;

content/renderer/OWNERS

@@ -14,3 +14,4 @@ per-file render_view_impl.*=fsamuel@chromium.org
 per-file render_widget.*=fsamuel@chromium.org
 per-file child_frame_compositor.*=fsamuel@chromium.org
 per-file child_frame_compositing_helper.*=fsamuel@chromium.org
+per-file render_frame_metadata*=fsamuel@chromium.org

content/renderer/render_frame_metadata_observer_impl.cc

@@ -4,6 +4,7 @@
 
 #include "content/renderer/render_frame_metadata_observer_impl.h"
 
+#include "build/build_config.h"
 #include "components/viz/common/quads/compositor_frame_metadata.h"
 
 namespace content {
@@ -40,7 +41,7 @@ void RenderFrameMetadataObserverImpl::OnRenderFrameSubmission(
                       *last_render_frame_metadata_ != render_frame_metadata;
     } else {
       send_metadata = !last_render_frame_metadata_ ||
-                      cc::RenderFrameMetadata::HasAlwaysUpdateMetadataChanged(
+                      ShouldSendRenderFrameMetadata(
                           *last_render_frame_metadata_, render_frame_metadata);
     }
   }
@@ -89,4 +90,30 @@ void RenderFrameMetadataObserverImpl::ReportAllFrameSubmissionsForTesting(
       last_frame_token_, *last_render_frame_metadata_);
 }
 
+// static
+bool RenderFrameMetadataObserverImpl::ShouldSendRenderFrameMetadata(
+    const cc::RenderFrameMetadata& rfm1,
+    const cc::RenderFrameMetadata& rfm2) {
+  return rfm1.root_background_color != rfm2.root_background_color ||
+         rfm1.is_scroll_offset_at_top != rfm2.is_scroll_offset_at_top ||
+         rfm1.selection != rfm2.selection ||
+         rfm1.page_scale_factor != rfm2.page_scale_factor ||
+#if defined(OS_ANDROID)
+         rfm1.top_controls_height != rfm2.top_controls_height ||
+         rfm1.top_controls_shown_ratio != rfm2.top_controls_shown_ratio ||
+         rfm1.bottom_controls_height != rfm2.bottom_controls_height ||
+         rfm1.bottom_controls_shown_ratio != rfm2.bottom_controls_shown_ratio ||
+         rfm1.min_page_scale_factor != rfm2.min_page_scale_factor ||
+         rfm1.max_page_scale_factor != rfm2.max_page_scale_factor ||
+         rfm1.root_overflow_y_hidden != rfm2.root_overflow_y_hidden ||
+         rfm1.scrollable_viewport_size != rfm2.scrollable_viewport_size ||
+         rfm1.root_layer_size != rfm2.root_layer_size ||
+         rfm1.has_transparent_background != rfm2.has_transparent_background ||
+#endif
+         rfm1.is_mobile_optimized != rfm2.is_mobile_optimized ||
+         rfm1.device_scale_factor != rfm2.device_scale_factor ||
+         rfm1.viewport_size_in_pixels != rfm2.viewport_size_in_pixels ||
+         rfm1.local_surface_id != rfm2.local_surface_id;
+}
+
 }  // namespace content

content/renderer/render_frame_metadata_observer_impl.h

@@ -40,6 +40,13 @@ class RenderFrameMetadataObserverImpl
   void ReportAllFrameSubmissionsForTesting(bool enabled) override;
 
  private:
+  // Certain fields should always have their changes reported. This will return
+  // true when there is a difference between |rfm1| and |rfm2| for those fields.
+  // These fields have a low frequency rate of change.
+  static bool ShouldSendRenderFrameMetadata(
+      const cc::RenderFrameMetadata& rfm1,
+      const cc::RenderFrameMetadata& rfm2);
+
   // When true this will notifiy |render_frame_metadata_observer_client_| of all
   // frame submissions.
   bool report_all_frame_submissions_for_testing_enabled_ = false;