Insert default stylesheet for platform apps.

chrome/renderer/extensions/extension_dispatcher.cc

Index: chrome/renderer/extensions/extension_dispatcher.cc
diff --git a/chrome/renderer/extensions/extension_dispatcher.cc b/chrome/renderer/extensions/extension_dispatcher.cc
index 9ed183928dfd4d046998e2a11da09f4c1641016d..3223ef559fcc42cb0489ed8688470dbc5924c393 100644
--- a/chrome/renderer/extensions/extension_dispatcher.cc
+++ b/chrome/renderer/extensions/extension_dispatcher.cc
@@ -29,6 +29,8 @@
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebSecurityPolicy.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebString.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebURLRequest.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebView.h"
+#include "ui/base/resource/resource_bundle.h"
 #include "v8/include/v8.h"
 
 namespace {
@@ -40,13 +42,16 @@ using WebKit::WebDataSource;
 using WebKit::WebFrame;
 using WebKit::WebSecurityPolicy;
 using WebKit::WebString;
+using WebKit::WebVector;
+using WebKit::WebView;
 using content::RenderThread;
 
 ExtensionDispatcher::ExtensionDispatcher()
     : is_webkit_initialized_(false),
       webrequest_adblock_(false),
       webrequest_adblock_plus_(false),
-      webrequest_other_(false) {
+      webrequest_other_(false),
+      is_batch_load_in_progress_(false) {
   const CommandLine& command_line = *(CommandLine::ForCurrentProcess());
   is_extension_process_ =
       command_line.HasSwitch(switches::kExtensionProcess) ||
@@ -71,6 +76,8 @@ bool ExtensionDispatcher::OnControlMessageReceived(
     IPC_MESSAGE_HANDLER(ExtensionMsg_DeliverMessage, OnDeliverMessage)
     IPC_MESSAGE_HANDLER(ExtensionMsg_SetFunctionNames, OnSetFunctionNames)
     IPC_MESSAGE_HANDLER(ExtensionMsg_Loaded, OnLoaded)
+    IPC_MESSAGE_HANDLER(ExtensionMsg_StartBatchLoad, OnStartBatchLoad)
+    IPC_MESSAGE_HANDLER(ExtensionMsg_EndBatchLoad, OnEndBatchLoad)
     IPC_MESSAGE_HANDLER(ExtensionMsg_Unloaded, OnUnloaded)
     IPC_MESSAGE_HANDLER(ExtensionMsg_SetScriptingWhitelist,
                         OnSetScriptingWhitelist)
@@ -189,6 +196,58 @@ void ExtensionDispatcher::OnLoaded(const ExtensionMsg_Loaded_Params& params) {
   }
 
   extensions_.Insert(extension);
+
+  if (extension->is_platform_app()) {
+    extensions_needing_stylesheet_.Insert(extension);
+    if (is_batch_load_in_progress_) {
+      // Do nothing; we'll expect the ExtensionMsg_EndBatchLoad message as our
+      // signal to do the cleanup work of creating a single stylesheet matching
+      // all the platform-app URL patterns observed in the batch.
+    } else {
+      DCHECK(extensions_needing_stylesheet_.size() == 1u);
+      // This ExtensionMsg_Loaded was not sent as part of a batch. But to
+      // simplify, let's treat it as a synthetic batch of one, then run the
+      // batch-ending code.
+      is_batch_load_in_progress_ = true;
+      OnEndBatchLoad();
+    }
+  }
+}
+
+void ExtensionDispatcher::OnStartBatchLoad() {
+  DCHECK(extensions_needing_stylesheet_.size() == 0u);
+  DCHECK(!is_batch_load_in_progress_);
+  is_batch_load_in_progress_ = true;
+}
+
+void ExtensionDispatcher::OnEndBatchLoad() {
+  DCHECK(is_batch_load_in_progress_);
+
+  // We have collected a set of platform-app extensions, so let's tell WebKit
+  // about them so that it can provide a default stylesheet for them.
+  //
+  // TODO: consider enhancing WebView to allow removing single stylesheets, or
+  // else to edit the pattern set associated with one.
+  std::vector<WebString> temp_patterns;
+  for (ExtensionSet::const_iterator i = extensions_needing_stylesheet_.begin();
+       i != extensions_needing_stylesheet_.end(); ++i) {
+    temp_patterns.push_back(
+        WebString::fromUTF8(i->second->url().spec() + "*"));
+  }
+  WebVector<WebString> patterns;
+  patterns.assign(temp_patterns);
+  if (patterns.size() > 0) {
+    WebView::addUserStyleSheet(
+        WebString::fromUTF8(ResourceBundle::GetSharedInstance().
+                            GetRawDataResource(IDR_PLATFORM_APP_CSS)),
+        patterns,
+        WebView::UserContentInjectInAllFrames,
+        WebView::UserStyleInjectInExistingDocuments);
+  }
+
+  // We have fully processed the batch. Clean things up for the next one.
+  extensions_needing_stylesheet_.Clear();
+  is_batch_load_in_progress_ = false;
 }
 
 void ExtensionDispatcher::OnUnloaded(const std::string& id) {
@@ -197,6 +256,10 @@ void ExtensionDispatcher::OnUnloaded(const std::string& id) {
   // we'd like it to get a new isolated world ID, so that it can pick up the
   // changed origin whitelist.
   user_script_slave_->RemoveIsolatedWorld(id);
+
+  // We don't do anything with existing platform-app stylesheets. They will
+  // stay resident, but the URL pattern corresponding to the unloaded
+  // extension's URL just won't match anything anymore.
 }
 
 void ExtensionDispatcher::OnSetScriptingWhitelist(