Add some error messages for setting wallpaper failures on Chrome(c++) side.

chrome/browser/chromeos/extensions/wallpaper_private_api.cc

Index: chrome/browser/chromeos/extensions/wallpaper_private_api.cc
diff --git a/chrome/browser/chromeos/extensions/wallpaper_private_api.cc b/chrome/browser/chromeos/extensions/wallpaper_private_api.cc
index 7c7e361b4c2e54bc6e5b270d2dd880b1c44179b7..ad6f58ea1b2e283f1bace10a3dd09a2224f0f5cb 100644
--- a/chrome/browser/chromeos/extensions/wallpaper_private_api.cc
+++ b/chrome/browser/chromeos/extensions/wallpaper_private_api.cc
@@ -99,7 +99,7 @@ class WallpaperFunctionBase::WallpaperDecoder : public ImageDecoder::Delegate {
     gfx::ImageSkia final_image(decoded_image);
     final_image.MakeThreadSafe();
     if (cancel_flag_.IsSet()) {
-      function_->OnFailureOrCancel();
+      function_->OnFailureOrCancel("Loading canceled");

[Nikita (slow), 2012/10/15 15:14:11]

I believe these should be taken from strings i.e. localized.

[bshe, 2012/10/17 00:13:51]

Pre discussion with kuscher, when wallpaper decoding is canceled, we dont want
any error message. We just show a new downloading bar. (it is handled in
javascript.)

On 2012/10/15 15:14:11, Nikita Kostylev wrote:

       delete this;
       return;
     }
@@ -108,8 +108,7 @@ class WallpaperFunctionBase::WallpaperDecoder : public ImageDecoder::Delegate {
   }
 
   virtual void OnDecodeImageFailed(const ImageDecoder* decoder) OVERRIDE {
-    function_->OnFailureOrCancel();
-    // TODO(bshe): Dispatches an encoding error event.
+    function_->OnFailureOrCancel("Loading failed");

[bshe, 2012/10/17 00:13:51]

Changed to localized string.

     delete this;
   }
 
@@ -130,6 +129,12 @@ WallpaperFunctionBase::WallpaperFunctionBase() {
 WallpaperFunctionBase::~WallpaperFunctionBase() {
 }
 
+void WallpaperFunctionBase::OnFailureOrCancel(const std::string& error) {
+  wallpaper_decoder_ = NULL;
+  SetResult(Value::CreateStringValue(error));
+  SendResponse(false);
+}
+
 WallpaperSetWallpaperFunction::WallpaperSetWallpaperFunction() {
 }
 
@@ -172,11 +177,6 @@ void WallpaperSetWallpaperFunction::OnWallpaperDecoded(
                  this));
 }
 
-void WallpaperSetWallpaperFunction::OnFailureOrCancel() {
-  wallpaper_decoder_ = NULL;
-  SendResponse(false);
-}
-
 void WallpaperSetWallpaperFunction::SaveToFile() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
   FilePath wallpaper_dir;
@@ -186,7 +186,7 @@ void WallpaperSetWallpaperFunction::SaveToFile() {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         base::Bind(&WallpaperSetWallpaperFunction::OnFailureOrCancel,
-                   this));
+                   this, "Failed to create directory"));

[bshe, 2012/10/17 00:13:51]

Pre discussion with kuscher, this case should be rare enough that a console
error message should be enough. Also line 215

     return;
   }
   std::string file_name = GURL(url_).ExtractFileName();
@@ -212,7 +212,7 @@ void WallpaperSetWallpaperFunction::SaveToFile() {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         base::Bind(&WallpaperSetWallpaperFunction::OnFailureOrCancel,
-                   this));
+                   this, "Failed to save downloaded wallpaper"));
   }
 }
 
@@ -229,6 +229,7 @@ void WallpaperSetWallpaperFunction::SetDecodedWallpaper() {
       base::Time::Now().LocalMidnight()
   };
   wallpaper_manager->SetUserWallpaperInfo(email_, info, is_persistent);
+  SetResult(Value::CreateStringValue(""));
   SendResponse(true);
 }
 
@@ -272,10 +273,6 @@ void WallpaperSetCustomWallpaperFunction::OnWallpaperDecoded(
       email_, layout_, chromeos::User::CUSTOMIZED,
       base::WeakPtr<chromeos::WallpaperDelegate>(), image);
   wallpaper_decoder_ = NULL;
+  SetResult(Value::CreateStringValue(""));
   SendResponse(true);
 }
-
-void WallpaperSetCustomWallpaperFunction::OnFailureOrCancel() {
-  wallpaper_decoder_ = NULL;
-  SendResponse(false);
-}