Restore SnapshotTabHelper temporarily until dependencies are fixed (reverts deletions in r189969). Do not use this class in Chrome.

BUG=223374
TBR=jam@, sky@

Review URL: https://codereview.chromium.org/12770014

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@190027 0039d316-1c4b-4281-b951-d872f2087c98

8 files changed, 156 insertions, 0 deletions

diff --git a/chrome/browser/ui/browser_tab_contents.cc b/chrome/browser/ui/browser_tab_contents.cc
index fad09c1..642370f 100644
--- a/chrome/browser/ui/browser_tab_contents.cc
+++ b/chrome/browser/ui/browser_tab_contents.cc
@@ -38,6 +38,7 @@
 #include "chrome/browser/ui/sad_tab_helper.h"
 #include "chrome/browser/ui/search/search_tab_helper.h"
 #include "chrome/browser/ui/search_engines/search_engine_tab_helper.h"
+#include "chrome/browser/ui/snapshot_tab_helper.h"
 #include "chrome/browser/ui/sync/tab_contents_synced_tab_delegate.h"
 #include "chrome/browser/ui/tab_contents/core_tab_helper.h"
 #include "chrome/browser/ui/web_contents_modal_dialog_manager.h"
@@ -144,6 +145,7 @@ void BrowserTabContents::AttachTabHelpers(WebContents* web_contents) {
   safe_browsing::SafeBrowsingTabObserver::CreateForWebContents(web_contents);
   SearchEngineTabHelper::CreateForWebContents(web_contents);
   chrome::search::SearchTabHelper::CreateForWebContents(web_contents);
+  SnapshotTabHelper::CreateForWebContents(web_contents);
   SSLTabHelper::CreateForWebContents(web_contents);
   TabContentsSyncedTabDelegate::CreateForWebContents(web_contents);
   TabSpecificContentSettings::CreateForWebContents(web_contents);
diff --git a/chrome/browser/ui/snapshot_tab_helper.cc b/chrome/browser/ui/snapshot_tab_helper.cc
new file mode 100644
index 0000000..76ed5ca
--- /dev/null
+++ b/chrome/browser/ui/snapshot_tab_helper.cc
@@ -0,0 +1,47 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/ui/snapshot_tab_helper.h"
+
+#include "chrome/common/chrome_notification_types.h"
+#include "chrome/common/render_messages.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/web_contents.h"
+
+using content::WebContents;
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(SnapshotTabHelper);
+
+SnapshotTabHelper::SnapshotTabHelper(WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {
+}
+
+SnapshotTabHelper::~SnapshotTabHelper() {
+}
+
+void SnapshotTabHelper::CaptureSnapshot() {
+  Send(new ChromeViewMsg_CaptureSnapshot(routing_id()));
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// WebContentsObserver overrides
+
+bool SnapshotTabHelper::OnMessageReceived(const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(SnapshotTabHelper, message)
+    IPC_MESSAGE_HANDLER(ChromeViewHostMsg_Snapshot, OnSnapshot)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+////////////////////////////////////////////////////////////////////////////////
+// Internal helpers
+
+void SnapshotTabHelper::OnSnapshot(const SkBitmap& bitmap) {
+  content::NotificationService::current()->Notify(
+      chrome::NOTIFICATION_TAB_SNAPSHOT_TAKEN,
+      content::Source<WebContents>(web_contents()),
+      content::Details<const SkBitmap>(&bitmap));
+}
diff --git a/chrome/browser/ui/snapshot_tab_helper.h b/chrome/browser/ui/snapshot_tab_helper.h
new file mode 100644
index 0000000..bde61b1
--- /dev/null
+++ b/chrome/browser/ui/snapshot_tab_helper.h
@@ -0,0 +1,38 @@
+// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_
+#define CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_
+
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+
+class SkBitmap;
+
+// Per-tab class to handle snapshot functionality.
+class SnapshotTabHelper
+    : public content::WebContentsObserver,
+      public content::WebContentsUserData<SnapshotTabHelper> {
+ public:
+  virtual ~SnapshotTabHelper();
+
+  // Captures a snapshot of the page.
+  void CaptureSnapshot();
+
+ private:
+  explicit SnapshotTabHelper(content::WebContents* web_contents);
+  friend class content::WebContentsUserData<SnapshotTabHelper>;
+
+  // content::WebContentsObserver overrides:
+  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+  // Internal helpers ----------------------------------------------------------
+
+  // Message handler.
+  void OnSnapshot(const SkBitmap& bitmap);
+
+  DISALLOW_COPY_AND_ASSIGN(SnapshotTabHelper);
+};
+
+#endif  // CHROME_BROWSER_UI_SNAPSHOT_TAB_HELPER_H_
diff --git a/chrome/chrome_browser_ui.gypi b/chrome/chrome_browser_ui.gypi
index 1e9bed1..1671876 100644
--- a/chrome/chrome_browser_ui.gypi
+++ b/chrome/chrome_browser_ui.gypi
@@ -1306,6 +1306,8 @@
         'browser/ui/simple_message_box.h',
         'browser/ui/singleton_tabs.cc',
         'browser/ui/singleton_tabs.h',
+        'browser/ui/snapshot_tab_helper.cc',
+        'browser/ui/snapshot_tab_helper.h',
         'browser/ui/startup/autolaunch_prompt.cc',
         'browser/ui/startup/autolaunch_prompt_win.cc',
         'browser/ui/startup/autolaunch_prompt.h',
diff --git a/chrome/common/chrome_content_client.cc b/chrome/common/chrome_content_client.cc
index 0bcc7a3..aaee0d8 100644
--- a/chrome/common/chrome_content_client.cc
+++ b/chrome/common/chrome_content_client.cc
@@ -399,6 +399,12 @@ bool ChromeContentClient::CanHandleWhileSwappedOut(
   // Any Chrome-specific messages (apart from those listed in
   // CanSendWhileSwappedOut) that must be handled by the browser when sent from
   // swapped out renderers.
+  switch (msg.type()) {
+    case ChromeViewHostMsg_Snapshot::ID:
+      return true;
+    default:
+      break;
+  }
   return false;
 }
 
diff --git a/chrome/common/render_messages.h b/chrome/common/render_messages.h
index 57e54f7..39e1077 100644
--- a/chrome/common/render_messages.h
+++ b/chrome/common/render_messages.h
@@ -263,6 +263,10 @@ IPC_MESSAGE_ROUTED4(ChromeViewMsg_WebUIJavaScript,
                     int,  /* ID */
                     bool  /* If true, result is sent back. */)
 
+// Tells the render view to capture a thumbnail image of the page. The
+// render view responds with a ChromeViewHostMsg_Snapshot.
+IPC_MESSAGE_ROUTED0(ChromeViewMsg_CaptureSnapshot)
+
 // Set the content setting rules stored by the renderer.
 IPC_MESSAGE_CONTROL1(ChromeViewMsg_SetContentSettingRules,
                      RendererContentSettingRules /* rules */)
@@ -551,6 +555,10 @@ IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_CouldNotLoadPlugin,
 IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_NPAPINotSupported,
                     std::string /* identifer */)
 
+// Send a snapshot of the tab contents to the render host.
+IPC_MESSAGE_ROUTED1(ChromeViewHostMsg_Snapshot,
+                    SkBitmap /* bitmap */)
+
 // A message for an external host.
 IPC_MESSAGE_ROUTED3(ChromeViewHostMsg_ForwardMessageToExternalHost,
                     std::string  /* message */,
diff --git a/chrome/renderer/chrome_render_view_observer.cc b/chrome/renderer/chrome_render_view_observer.cc
index 48651a7..020979a 100644
--- a/chrome/renderer/chrome_render_view_observer.cc
+++ b/chrome/renderer/chrome_render_view_observer.cc
@@ -194,6 +194,7 @@ bool ChromeRenderViewObserver::OnMessageReceived(const IPC::Message& message) {
   bool handled = true;
   IPC_BEGIN_MESSAGE_MAP(ChromeRenderViewObserver, message)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_WebUIJavaScript, OnWebUIJavaScript)
+    IPC_MESSAGE_HANDLER(ChromeViewMsg_CaptureSnapshot, OnCaptureSnapshot)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_HandleMessageFromExternalHost,
                         OnHandleMessageFromExternalHost)
     IPC_MESSAGE_HANDLER(ChromeViewMsg_JavaScriptStressTestControl,
@@ -235,6 +236,24 @@ void ChromeRenderViewObserver::OnWebUIJavaScript(
   webui_javascript_->notify_result = notify_result;
 }
 
+void ChromeRenderViewObserver::OnCaptureSnapshot() {
+  SkBitmap snapshot;
+  bool error = false;
+
+  WebFrame* main_frame = render_view()->GetWebView()->mainFrame();
+  if (!main_frame)
+    error = true;
+
+  if (!error && !CaptureSnapshot(render_view()->GetWebView(), &snapshot))
+    error = true;
+
+  DCHECK(error == snapshot.empty()) <<
+      "Snapshot should be empty on error, non-empty otherwise.";
+
+  // Send the snapshot to the browser process.
+  Send(new ChromeViewHostMsg_Snapshot(routing_id(), snapshot));
+}
+
 void ChromeRenderViewObserver::OnHandleMessageFromExternalHost(
     const std::string& message,
     const std::string& origin,
@@ -776,6 +795,35 @@ void ChromeRenderViewObserver::CaptureText(WebFrame* frame,
   }
 }
 
+bool ChromeRenderViewObserver::CaptureSnapshot(WebView* view,
+                                               SkBitmap* snapshot) {
+  base::TimeTicks beginning_time = base::TimeTicks::Now();
+
+  view->layout();
+  const WebSize& size = view->size();
+
+  skia::RefPtr<SkCanvas> canvas = skia::AdoptRef(
+      skia::CreatePlatformCanvas(
+          size.width, size.height, true, NULL, skia::RETURN_NULL_ON_FAILURE));
+  if (!canvas)
+    return false;
+
+  view->paint(webkit_glue::ToWebCanvas(canvas.get()),
+              WebRect(0, 0, size.width, size.height));
+  // TODO: Add a way to snapshot the whole page, not just the currently
+  // visible part.
+
+  SkDevice* device = skia::GetTopDevice(*canvas);
+
+  const SkBitmap& bitmap = device->accessBitmap(false);
+  if (!bitmap.copyTo(snapshot, SkBitmap::kARGB_8888_Config))
+    return false;
+
+  UMA_HISTOGRAM_TIMES("Renderer4.Snapshot",
+                  base::TimeTicks::Now() - beginning_time);
+  return true;
+}
+
 ExternalHostBindings* ChromeRenderViewObserver::GetExternalHostBindings() {
   if (!external_host_bindings_.get()) {
     external_host_bindings_.reset(new ExternalHostBindings(
diff --git a/chrome/renderer/chrome_render_view_observer.h b/chrome/renderer/chrome_render_view_observer.h
index d5297c8..80247ff 100644
--- a/chrome/renderer/chrome_render_view_observer.h
+++ b/chrome/renderer/chrome_render_view_observer.h
@@ -126,6 +126,7 @@ class ChromeRenderViewObserver : public content::RenderViewObserver,
                          const string16& jscript,
                          int id,
                          bool notify_result);
+  void OnCaptureSnapshot();
   void OnHandleMessageFromExternalHost(const std::string& message,
                                        const std::string& origin,
                                        const std::string& target);
@@ -149,6 +150,10 @@ class ChromeRenderViewObserver : public content::RenderViewObserver,
   // maximum amount kMaxIndexChars will be placed into the given buffer.
   void CaptureText(WebKit::WebFrame* frame, string16* contents);
 
+  // Capture a snapshot of a view.  This is used to allow an extension
+  // to get a snapshot of a tab using chrome.tabs.captureVisibleTab().
+  bool CaptureSnapshot(WebKit::WebView* view, SkBitmap* snapshot);
+
   ExternalHostBindings* GetExternalHostBindings();
 
   // Determines if a host is in the strict security host set.