cheets: add wallpaper observer to arc_wallpaper_service.

ArcWallpaperService now observes wallpaper change
and notifies Android, which will use it to broadcast
ACTION_WALLPAPER_CHANGED.

Test=Change wallpaper with CrOS wallpaper picker
  and verify with Android app that listens wallpaper
  changed broadcast.

Bug=642465

Review-Url: https://codereview.chromium.org/2345153002
Cr-Commit-Position: refs/heads/master@{#419303}

chrome/browser/chromeos/arc/arc_wallpaper_service.cc

@@ -4,8 +4,6 @@
 
 #include "chrome/browser/chromeos/arc/arc_wallpaper_service.h"
 
-#include <string>
-#include <utility>
 #include <vector>
 
 #include "ash/common/wallpaper/wallpaper_controller.h"
@@ -31,6 +29,7 @@ namespace arc {
 
 namespace {
 
+constexpr uint32_t kMinOnWallpaperChangedVersion = 1;
 constexpr char kAndroidWallpaperFilename[] = "android.jpg";
 
 // Sets a decoded bitmap as the wallpaper.
@@ -69,6 +68,13 @@ std::vector<uint8_t> EncodeImagePng(const gfx::ImageSkia image) {
   return result;
 }
 
+ash::WallpaperController* GetWallpaperController() {
+  ash::WmShell* wm_shell = ash::WmShell::Get();
+  if (!wm_shell)
+    return nullptr;
+  return wm_shell->wallpaper_controller();
+}
+
 }  // namespace
 
 ArcWallpaperService::ArcWallpaperService(ArcBridgeService* bridge_service)
@@ -81,6 +87,9 @@ ArcWallpaperService::~ArcWallpaperService() {
   // Make sure the callback is never called after destruction. It is safe to
   // call Cancel() even when there is no in-flight request.
   ImageDecoder::Cancel(this);
+  ash::WallpaperController* wc = GetWallpaperController();
+  if (wc)
+    wc->RemoveObserver(this);
   arc_bridge_service()->wallpaper()->RemoveObserver(this);
 }
 
@@ -94,6 +103,14 @@ void ArcWallpaperService::OnInstanceReady() {
     return;
   }
   wallpaper_instance->Init(binding_.CreateInterfacePtrAndBind());
+  ash::WmShell::Get()->wallpaper_controller()->AddObserver(this);
+}
+
+void ArcWallpaperService::OnInstanceClosed() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  ash::WallpaperController* wc = GetWallpaperController();
+  if (wc)
+    wc->RemoveObserver(this);
 }
 
 void ArcWallpaperService::SetWallpaper(mojo::Array<uint8_t> png_data) {
@@ -122,4 +139,29 @@ void ArcWallpaperService::OnDecodeImageFailed() {
   LOG(ERROR) << "Failed to decode wallpaper image.";
 }
 
+void ArcWallpaperService::OnWallpaperDataChanged() {
+  DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
+  mojom::WallpaperInstance* instance =
+      GetWallpaperInstance(kMinOnWallpaperChangedVersion);
+  if (!instance)
+    return;
+  instance->OnWallpaperChanged();
+}
+
+mojom::WallpaperInstance* ArcWallpaperService::GetWallpaperInstance(
+    uint32_t min_version) {
+  uint32_t version = arc_bridge_service()->wallpaper()->version();
+  if (version < min_version) {
+    VLOG(1) << "ARC wallpaper instance is too old. required: " << min_version
+            << ", actual: " << version;
+    return nullptr;
+  }
+
+  mojom::WallpaperInstance* instance =
+      arc_bridge_service()->wallpaper()->instance();
+  if (!instance)
+    VLOG(2) << "ARC wallpaper instance is not ready.";
+  return instance;
+}
+
 }  // namespace arc

chrome/browser/chromeos/arc/arc_wallpaper_service.h

@@ -7,10 +7,7 @@
 
 #include <stdint.h>
 
-#include <memory>
-#include <set>
-#include <vector>
-
+#include "ash/common/wallpaper/wallpaper_controller_observer.h"
 #include "base/macros.h"
 #include "chrome/browser/image_decoder.h"
 #include "components/arc/arc_service.h"
@@ -25,6 +22,7 @@ namespace arc {
 // Lives on the UI thread.
 class ArcWallpaperService
     : public ArcService,
+      public ash::WallpaperControllerObserver,
       public ImageDecoder::ImageRequest,
       public InstanceHolder<mojom::WallpaperInstance>::Observer,
       public mojom::WallpaperHost {
@@ -34,6 +32,7 @@ class ArcWallpaperService
 
   // InstanceHolder<mojom::WallpaperInstance>::Observer overrides.
   void OnInstanceReady() override;
+  void OnInstanceClosed() override;
 
   // mojom::WallpaperHost overrides.
   // TODO(muyuanli): change callback prototype when use_new_wrapper_types is
@@ -45,7 +44,12 @@ class ArcWallpaperService
   void OnImageDecoded(const SkBitmap& bitmap) override;
   void OnDecodeImageFailed() override;
 
+  // WallpaperControllerObserver implementation.
+  void OnWallpaperDataChanged() override;
+
  private:
+  mojom::WallpaperInstance* GetWallpaperInstance(uint32_t min_version);
+
   mojo::Binding<mojom::WallpaperHost> binding_;
   DISALLOW_COPY_AND_ASSIGN(ArcWallpaperService);
 };

components/arc/common/wallpaper.mojom

@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
-// Next MinVersion: 1
+// Next MinVersion: 2
 
 module arc.mojom;
 
@@ -18,8 +18,11 @@ interface WallpaperHost {
 };
 
 // Connects with container side to publish wallpaper related intents.
-// Next method ID:1
+// Next method ID:2
 interface WallpaperInstance {
   // Establishes communication with the container side.
   Init@0(WallpaperHost host_ptr);
+
+  // Notifies ArcWallpaperManagerService that wallpaper is changed.
+  [MinVersion=1] OnWallpaperChanged@1();
 };
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