Make image_decoder a Leaky LazyInstance

chrome/browser/extensions/webstore_install_helper.cc

Index: chrome/browser/extensions/webstore_install_helper.cc
diff --git a/chrome/browser/extensions/webstore_install_helper.cc b/chrome/browser/extensions/webstore_install_helper.cc
index 47926c6954258886f6a7ae4154a9f3638552dccc..e56cddc3c51115578ea4564a2645c91e527f531e 100644
--- a/chrome/browser/extensions/webstore_install_helper.cc
+++ b/chrome/browser/extensions/webstore_install_helper.cc
@@ -32,13 +32,11 @@ WebstoreInstallHelper::WebstoreInstallHelper(
     Delegate* delegate,
     const std::string& id,
     const std::string& manifest,
-    const std::string& icon_data,
     const GURL& icon_url,
     net::URLRequestContextGetter* context_getter)
     : delegate_(delegate),
       id_(id),
       manifest_(manifest),
-      icon_base64_data_(icon_data),
       icon_url_(icon_url),
       context_getter_(context_getter),
       icon_decode_complete_(false),
@@ -49,9 +47,8 @@ WebstoreInstallHelper::~WebstoreInstallHelper() {}
 
 void WebstoreInstallHelper::Start() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
-  CHECK(icon_base64_data_.empty() || icon_url_.is_empty());
 
-  if (icon_base64_data_.empty() && icon_url_.is_empty())
+  if (icon_url_.is_empty())
     icon_decode_complete_ = true;
 
   BrowserThread::PostTask(
@@ -78,10 +75,6 @@ void WebstoreInstallHelper::StartWorkOnIOThread() {
       this, base::MessageLoopProxy::current().get())->AsWeakPtr();
   utility_host_->StartBatchMode();
 
-  if (!icon_base64_data_.empty())
-    utility_host_->Send(
-        new ChromeUtilityMsg_DecodeImageBase64(icon_base64_data_));
-
   utility_host_->Send(new ChromeUtilityMsg_ParseJSON(manifest_));
 }
 
@@ -94,8 +87,7 @@ void WebstoreInstallHelper::OnURLFetchComplete(
   if (!source->GetStatus().is_success() ||
       response_code / 100 == 4 || response_code / 100 == 5) {
     BrowserThread::PostTask(
-        BrowserThread::IO,
-        FROM_HERE,
+        BrowserThread::IO, FROM_HERE,
         base::Bind(&WebstoreInstallHelper::OnDecodeImageFailed, this));
   } else {
     std::string response_data;
@@ -113,19 +105,17 @@ void WebstoreInstallHelper::OnURLFetchComplete(
 
 void WebstoreInstallHelper::StartFetchedImageDecode() {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
-  CHECK(utility_host_.get());
-  utility_host_->Send(new ChromeUtilityMsg_DecodeImage(fetched_icon_data_,
-                                                       false));
+  ImageDecoder::GetInstance()->Start(
+      this, std::string(fetched_icon_data_.begin(), fetched_icon_data_.end()),

[asargent_no_longer_on_chrome, 2015/03/12 21:40:08]

I think we should just change fetched_icon_data_ to be a std::string instead of
std::vector<unsigned char>, and up in ::OnURLFetchComplete around line 94 we can
grab the response from the URLFetch and put it directly into fetched_icon_data_
instead of the response_data temporary. 

That might also save a copy of the bytes into the temporary std::string here on
line 109 (I'm not sure off the top of my head whether the compiler would be
smart enough to optimize that away or not). 

[Theresa, 2015/03/12 22:19:10]

Good catch :) Instead of doing that, I removed this method
(StartFetchedImageDecode) and call ImageDecoder::GetInstance()->Start directly
from OnURLFetchComplete. StartFetchedImageDecode used to be needed because
interaction with the utility process had to happen on the IO thread, but calling
ImageDecoder::GetInstance()->Start can happen from any thread. This change also
removed the need for fetched_icon_data_ so I delete that variable as well.

+      ImageDecoder::DEFAULT_CODEC,
+      content::BrowserThread::GetMessageLoopProxyForThread(
+          content::BrowserThread::IO),
+      false);
 }
 
-
 bool WebstoreInstallHelper::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(WebstoreInstallHelper, message)
-    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_DecodeImage_Succeeded,
-                        OnDecodeImageSucceeded)
-    IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_DecodeImage_Failed,
-                        OnDecodeImageFailed)
     IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_ParseJSON_Succeeded,
                         OnJSONParseSucceeded)
     IPC_MESSAGE_HANDLER(ChromeUtilityHostMsg_ParseJSON_Failed,
@@ -135,9 +125,7 @@ bool WebstoreInstallHelper::OnMessageReceived(const IPC::Message& message) {
   return handled;
 }
 
-
-void WebstoreInstallHelper::OnDecodeImageSucceeded(
-    const SkBitmap& decoded_image) {
+void WebstoreInstallHelper::OnImageDecoded(const SkBitmap& decoded_image) {
   CHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
   icon_ = decoded_image;
   icon_decode_complete_ = true;