Clean up error handling logic for extension tab muting

chrome/browser/ui/tabs/tab_utils.h

 // 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_TABS_TAB_UTILS_H_
 #define CHROME_BROWSER_UI_TABS_TAB_UTILS_H_
 
 #include <string>
 #include <vector>
-
+#include "base/containers/hash_tables.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/strings/string16.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 class TabStripModel;
 
 namespace content {
 class WebContents;
 }  // namespace content
 
 namespace gfx {
 class Animation;
 class Image;
 }  // namespace gfx
 
 // Media state for a tab.  In reality, more than one of these may apply.  See
 // comments for GetTabMediaStateForContents() below.
 enum TabMediaState {
   TAB_MEDIA_STATE_NONE,
   TAB_MEDIA_STATE_RECORDING,  // Audio/Video being recorded, consumed by tab.
   TAB_MEDIA_STATE_CAPTURING,  // Tab contents being captured.
   TAB_MEDIA_STATE_AUDIO_PLAYING,  // Audible audio is playing from the tab.
   TAB_MEDIA_STATE_AUDIO_MUTING,  // Tab audio is being muted.
 };
 
+enum TabMutedResult {
+  TAB_MUTED_RESULT_SUCCESS,
+  TAB_MUTED_RESULT_FAIL_NOT_ENABLED,
+  TAB_MUTED_RESULT_FAIL_TABCAPTURE,
+  TAB_MUTED_RESULT_FAIL_RATE_LIMITED,
+};
+
 namespace chrome {
 
 // String to indicate reason for muted state change (user, capture, extension
 // id, or empty string)
 extern const char kMutedToggleCauseUser[];
 extern const char kMutedToggleCauseCapture[];
 
+// Constants for rate limiting mute updating by extensions
+extern const int kMuteTokenBucketCostSeconds = 15;

[miu, 2015/07/16 00:28:26]

style nit: Assignment of the constant needs to be in the .cc file (see my
example from last round of review comments).

Alternatively, you could define these two constants as:

enum {
  kMuteTokenBucketCostSeconds = 15,
  kMuteTokenBucketCapacitySeconds = 45
};

+extern const int kMuteTokenBucketCapacitySeconds =
+    3 * kMuteTokenBucketCostSeconds;
+
 // Logic to determine which components (i.e., close button, favicon, and media
 // indicator) of a tab should be shown, given current state.  |capacity|
 // specifies how many components can be shown, given available tab width.
 //
 // Precedence rules for deciding what to show when capacity is insufficient to
 // show everything:
 //
 //   Active tab: Always show the close button, then the media indicator, then
 //               the favicon.
 //   Inactive tab: Media indicator, then the favicon, then the close button.
@@ skipping 44 matching lines @@
 base::string16 AssembleTabTooltipText(const base::string16& title,
                                       TabMediaState media_state);
 
 // Returns true if the experimental tab audio mute feature is enabled.
 bool IsTabAudioMutingFeatureEnabled();
 
 // Returns true if audio mute can be activated/deactivated for the given
 // |contents|.
 bool CanToggleAudioMute(content::WebContents* contents);
 
+// Returns true if extension-driven muting is rate limited for a tab
+bool IsTabAudioMutedRateLimited(content::WebContents* contents);
+
 // Indicates whether all audio output from |contents| is muted.
 bool IsTabAudioMuted(content::WebContents* contents);
 
 // Sets whether all audio output from |contents| is muted.
 // Cause is extensionid, kMutedToggleCause constant, or empty string
-void SetTabAudioMuted(content::WebContents* contents,
-                      bool mute,
-                      const std::string& cause);
+TabMutedResult SetTabAudioMuted(content::WebContents* contents,
+                                bool mute,
+                                const std::string& cause);
 
 // Get cause of mute (extensionid, kMutedToggleCause constant, or empty string)
 const std::string& GetTabAudioMutedCause(content::WebContents* contents);
 
+// Update token buckets for rate limiting muting using elapsed time
+void updateTokenBuckets(content::WebContents* contents);

[miu, 2015/07/16 00:28:26]

Also, don't declare this function in the header file.  It should be private
within tab_utils.cc.

[miu, 2015/07/16 00:28:26]

style: The "u" in updateTokenBuckets needs to be captialized.

+
 // Returns true if the tabs at the |indices| in |tab_strip| are all muted.
 bool AreAllTabsMuted(const TabStripModel& tab_strip,
                      const std::vector<int>& indices);
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_UI_TABS_TAB_UTILS_H_