Introduce new async IPC message to get file icons

chrome/browser/renderer_host/render_view_host.cc

Index: chrome/browser/renderer_host/render_view_host.cc
===================================================================
--- chrome/browser/renderer_host/render_view_host.cc	(revision 46794)
+++ chrome/browser/renderer_host/render_view_host.cc	(working copy)
@@ -15,11 +15,14 @@
 #include "base/string_util.h"
 #include "base/time.h"
 #include "base/waitable_event.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/child_process_security_policy.h"
 #include "chrome/browser/cross_site_request_manager.h"
+#include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/debugger/devtools_manager.h"
 #include "chrome/browser/dom_operation_notification_details.h"
 #include "chrome/browser/extensions/extension_message_service.h"
+#include "chrome/browser/icon_manager.h"
 #include "chrome/browser/metrics/user_metrics.h"
 #include "chrome/browser/notifications/desktop_notification_service.h"
 #include "chrome/browser/profile.h"
@@ -39,6 +42,7 @@
 #include "chrome/common/thumbnail_score.h"
 #include "chrome/common/translate_errors.h"
 #include "chrome/common/url_constants.h"
+#include "gfx/codec/png_codec.h"
 #include "gfx/native_widget_types.h"
 #include "net/base/net_util.h"
 #include "third_party/skia/include/core/SkBitmap.h"
@@ -756,6 +760,7 @@
                         OnMsgGoToEntryAtOffset)
     IPC_MESSAGE_HANDLER(ViewHostMsg_SetTooltipText, OnMsgSetTooltipText)
     IPC_MESSAGE_HANDLER(ViewHostMsg_RunFileChooser, OnMsgRunFileChooser)
+    IPC_MESSAGE_HANDLER(ViewHostMsg_ChooseIconForFiles, OnMsgChooseIconForFiles)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(ViewHostMsg_RunJavaScriptMessage,
                                     OnMsgRunJavaScriptMessage)
     IPC_MESSAGE_HANDLER_DELAY_REPLY(ViewHostMsg_RunBeforeUnloadConfirm,
@@ -1315,6 +1320,115 @@
   delegate_->RunFileChooser(params);
 }
 
+// Manages cancelable icon loading.
+class IconRequestProvider : public CancelableRequestProvider {
+ public:
+  typedef Callback2<int, SkBitmap*>::Type RequestCallbackType;
+  typedef CancelableRequest<RequestCallbackType> RequestType;
+
+  Handle Start(int request_id, const std::vector<FilePath>& filenames,
+               CancelableRequestConsumerBase* consumer,
+               RequestCallbackType* callback);
+
+ private:
+  CancelableRequestConsumerT<int, 0> consumer_;
+};
+
+// Helper for OnMsgChooseIconForFiles().
+// This instance runs in the UI thread.
+class IconRequestBackend : public
+    base::RefCountedThreadSafe<IconRequestBackend> {
+ public:
+  explicit IconRequestBackend(
+      scoped_refptr<IconRequestProvider::RequestType> request,
+      CancelableRequestConsumerBase* consumer,
+      int request_id,
+      const std::vector<FilePath>& filenames)
+      : request_(request),
+      consumer_(consumer),
+      request_id_(request_id),
+      filenames_(filenames) { }
+
+  void Run() {
+    if (request_->canceled()) {
+      Release();
+      return;
+    }
+
+    IconManager* im = g_browser_process->icon_manager();
+    if (filenames_.size() <= 0) {
+      Reply(NULL);
+    } else {
+      // TODO(tkent): Load an icon representing `multiple files' in a case of
+      // filenames_.size() > 1.
+      SkBitmap* icon = im->LookupIcon(filenames_[0], IconLoader::NORMAL);
+      if (icon) {
+        Reply(icon);
+        return;
+      }
+      im->LoadIcon(filenames_[0], IconLoader::NORMAL, consumer_,
+          NewCallback(this, &IconRequestBackend::OnIconLoaded));
+    }
+  }
+
+ private:
+  ~IconRequestBackend() { }
+
+  void Reply(SkBitmap* icon) {
+    request_->ForwardResult(Tuple2<int, SkBitmap*>(request_id_, icon));
+    Release();
+  }
+
+  void OnIconLoaded(IconManager::Handle handle, SkBitmap* icon) {
+    Reply(icon);
+  }
+
+  scoped_refptr<IconRequestProvider::RequestType> request_;
+  // CancelableRequestConsumer for IconManager.
+  CancelableRequestConsumerBase* consumer_;
+  // Copy of a ViewHostMsg_IconForFiles arguemnt.
+  int request_id_;
+  // Copy of a ViewHostMsg_IconForFiles arguemnt.
+  const std::vector<FilePath> filenames_;
+
+  friend class base::RefCountedThreadSafe<IconRequestBackend>;
+};
+
+IconRequestProvider::Handle IconRequestProvider::Start(
+    int request_id,
+    const std::vector<FilePath>& filenames,
+    CancelableRequestConsumerBase* consumer,
+    RequestCallbackType* callback) {
+  scoped_refptr<RequestType> request(new RequestType(callback));
+  AddRequest(request, consumer);
+
+  IconRequestBackend* backend =
+      new IconRequestBackend(request, &consumer_, request_id, filenames);
+  backend->AddRef();
+  // We need to switch to the UI thread because IconManager works
+  // only in the UI thread.
+  ChromeThread::PostTask(ChromeThread::UI, FROM_HERE,
+      NewRunnableMethod(backend, &IconRequestBackend::Run));
+  return request->handle();
+}
+
+void RenderViewHost::OnIconLoaded(int request_id, SkBitmap* icon) {
+  std::vector<unsigned char> png_data;
+  gfx::PNGCodec::EncodeBGRASkBitmap(*icon, false, &png_data);
+  Send(new ViewMsg_ChooseIconForFilesResponse(
+      routing_id(), request_id, png_data));
+  // No need to delete |icon|.  It is owned by IconManager.
+}
+
+void RenderViewHost::OnMsgChooseIconForFiles(
+    int request_id, const std::vector<FilePath>& filenames) {
+  if (icon_request_provider_.get() == NULL) {
+    icon_request_provider_.reset(new IconRequestProvider());
+  }
+  icon_request_provider_->Start(request_id, filenames, &cancelable_consumer_,
+    NewCallback(this, &RenderViewHost::OnIconLoaded));
+}
+
 void RenderViewHost::OnMsgRunJavaScriptMessage(
     const std::wstring& message,
     const std::wstring& default_prompt,