screenshot disabling policy

chrome/browser/ui/views/ash/screenshot_taker.cc

 // 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/views/ash/screenshot_taker.h"
 
 #include <climits>
 #include <string>
 
 #include "ash/shell.h"
 #include "ash/shell_delegate.h"
 #include "ash/shell_window_ids.h"
 #include "base/bind.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/i18n/time_formatting.h"
 #include "base/logging.h"
 #include "base/memory/ref_counted_memory.h"
 #include "base/stringprintf.h"
 #include "base/time.h"
+#include "chrome/browser/browser_process.h"
 #include "chrome/browser/download/download_prefs.h"
 #include "chrome/browser/prefs/pref_service.h"
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/window_snapshot/window_snapshot.h"
 #include "chrome/common/pref_names.h"
 #include "content/public/browser/browser_thread.h"
 #include "ui/aura/root_window.h"
 #include "ui/aura/window.h"
 
@@ skipping 75 matching lines @@
           reinterpret_cast<char*>(&(png_data->data()[0])),
           png_data->size())) != png_data->size()) {
     LOG(ERROR) << "Failed to save to " << screenshot_path.value();
   }
 }
 
 bool GrabWindowSnapshot(aura::Window* window,
                         const gfx::Rect& snapshot_bounds,
                         std::vector<unsigned char>* png_data) {
 #if defined(OS_LINUX)
+  // browser::GrabWindowSnapshot checks this too, but RootWindow::GrabSnapshot
+  // does not. The statement below is only to support linux-specific XGetImage
+  // optimization.
+  if (g_browser_process->local_state()->GetBoolean(prefs::kDisableScreenshots))
+    return false;

[sky, 2012/07/17 22:05:57]

This is going to result in a LOG(ERROR) on line 180ish, which I don't think
makes sense here. Maybe you should put this check in HandleTakePartialScreenshot
so that we early out there.

[qfel, 2012/07/18 09:24:27]

In any case, I think we should leave GrabWindowSnapshot as is (safer, policy
checked in one place), and eventually do redundant checks elsewhere
(HandleTakePartialScreenshot) for nicer log output.
Added check in HandleTakePartialScreenshot.

+
   // We use XGetImage() for Linux/ChromeOS for performance reasons.
   // See crbug.com/119492
   // TODO(mukai): remove this when the performance issue has been fixed.
   if (window->GetRootWindow()->GrabSnapshot(snapshot_bounds, png_data))
     return true;
 #endif  // OS_LINUX
 
   return browser::GrabWindowSnapshot(window, png_data, snapshot_bounds);
 }
 
@@ skipping 67 matching lines @@
       ash::internal::kShellWindowId_OverlayContainer)->layer();
   parent->Add(visual_feedback_layer_.get());
   visual_feedback_layer_->SetVisible(true);
 
   MessageLoopForUI::current()->PostDelayedTask(
       FROM_HERE,
       base::Bind(&ScreenshotTaker::CloseVisualFeedbackLayer,
                  base::Unretained(this)),
       base::TimeDelta::FromMilliseconds(kVisualFeedbackLayerDisplayTimeMs));
 }