[ash-md] WIP Added wallpaper color caching.

ash/common/wallpaper/wallpaper_controller.cc

Index: ash/common/wallpaper/wallpaper_controller.cc
diff --git a/ash/common/wallpaper/wallpaper_controller.cc b/ash/common/wallpaper/wallpaper_controller.cc
index d1b23e276bf7cd4108002542dbe59ca57c7c9bb2..d3671db05911b63e57e008b2444f8fac078a6919 100644
--- a/ash/common/wallpaper/wallpaper_controller.cc
+++ b/ash/common/wallpaper/wallpaper_controller.cc
@@ -21,6 +21,7 @@
 #include "base/command_line.h"
 #include "base/logging.h"
 #include "base/task_runner.h"
+#include "components/wallpaper/wallpaper_color_cache.h"
 #include "components/wallpaper/wallpaper_color_calculator.h"
 #include "components/wallpaper/wallpaper_resizer.h"
 #include "ui/display/manager/managed_display_info.h"
@@ -71,6 +72,7 @@ WallpaperController::WallpaperController(
     const scoped_refptr<base::TaskRunner>& task_runner)
     : locked_(false),
       wallpaper_mode_(WALLPAPER_NONE),
+      color_cache_(nullptr),
       prominent_color_(SK_ColorTRANSPARENT),
       wallpaper_reload_delay_(kWallpaperReloadDelayMs),
       task_runner_(task_runner) {
@@ -245,6 +247,12 @@ void WallpaperController::OpenSetWallpaperPage() {
   }
 }
 
+void WallpaperController::SetWallpaperColorCache(
+    wallpaper::WallpaperColorCache* color_cache) {
+  CHECK(!color_cache_);
+  color_cache_ = color_cache;
+}
+
 void WallpaperController::SetWallpaperPicker(mojom::WallpaperPickerPtr picker) {
   wallpaper_picker_ = std::move(picker);
 }
@@ -263,6 +271,12 @@ void WallpaperController::OnWallpaperResized() {
 
 void WallpaperController::OnColorCalculationComplete() {
   const SkColor color = color_calculator_->prominent_color();
+
+  if (color_cache_) {
+    // TODO(bruthig): GetWallpaperOriginalImageId() is insufficient!!
+    color_cache_->SetColor(GetWallpaperOriginalImageId(), color);
+  }
+
   color_calculator_.reset();
   SetProminentColor(color);
 }
@@ -353,6 +367,17 @@ void WallpaperController::CalculateWallpaperColors() {
   if (color_calculator_)
     color_calculator_->RemoveObserver(this);
 
+  color_calculator_.reset();
+
+  if (color_cache_) {
+    SkColor color;
+    // TODO(bruthig): GetWallpaperOriginalImageId() is insufficient!!
+    if (color_cache_->GetColor(GetWallpaperOriginalImageId(), &color)) {
+      SetProminentColor(color);
+      return;
+    }
+  }
+
   color_calculator_ = base::MakeUnique<wallpaper::WallpaperColorCalculator>(
       GetWallpaper(), luma, saturation, task_runner_);
   color_calculator_->AddObserver(this);