Handling volume up/down/mute keypresses within Chrome.

When Window Manager sends us a NOTIFY_SYSKEY_CLICKED message,
we adjust the volume accordingly.  Currently just calling
amixer as WM was doing before.  There will be a different
change submitted for WM to send this message instead of
calling amixer itself.

Patch by davej@chromium.org:
http://codereview.chromium.org/2102001/show

BUG=cros/525
TEST=none

Related to issue 2107001.

Review URL: http://codereview.chromium.org/2107010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@47451 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 119 insertions, 0 deletions

diff --git a/chrome/browser/chromeos/system_key_event_listener.cc b/chrome/browser/chromeos/system_key_event_listener.cc
new file mode 100644
index 0000000..b5f53f0
--- /dev/null
+++ b/chrome/browser/chromeos/system_key_event_listener.cc
@@ -0,0 +1,78 @@
+// Copyright (c) 2010 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/chromeos/system_key_event_listener.h"
+
+#include "third_party/cros/chromeos_wm_ipc_enums.h"
+
+namespace chromeos {
+
+// For now, this file contains the SystemKeyEventListener, which listens for key
+// presses from Window Manager, and just calls amixer to adjust volume.  Start
+// by just calling instance() to get it going.
+//
+// TODO(davej): Create AudioHandler() class and call its volume up/down/mute
+// functions, getting rid of these constants and RunCommand().  This class will
+// eventually call PulseAudio directly to get current volume and adjust
+// accordingly, giving us more control over Mute/UnMute behavior as well.
+
+namespace {
+
+const char kIncreaseVolumeLevelCommand[] =
+    "/usr/bin/amixer -- sset Master unmute 5%+";
+const char kDecreaseVolumeLevelCommand[] =
+    "/usr/bin/amixer -- sset Master unmute 5%-";
+const char kMuteAudioCommand[] =
+    "/usr/bin/amixer -- sset Master mute";
+
+}  // namespace
+
+// static
+SystemKeyEventListener* SystemKeyEventListener::instance() {
+  SystemKeyEventListener* instance = Singleton<SystemKeyEventListener>::get();
+  return instance;
+}
+
+SystemKeyEventListener::SystemKeyEventListener() {
+  WmMessageListener::instance()->AddObserver(this);
+}
+
+SystemKeyEventListener::~SystemKeyEventListener() {
+  WmMessageListener::instance()->RemoveObserver(this);
+}
+
+void SystemKeyEventListener::ProcessWmMessage(const WmIpc::Message& message,
+                                              GdkWindow* window) {
+  if (message.type() != WM_IPC_MESSAGE_CHROME_NOTIFY_SYSKEY_PRESSED)
+    return;
+
+  // TODO(davej): Use WmIpcSystemKey enums when available.
+  switch (message.param(0)) {
+    case 0:
+      RunCommand(kMuteAudioCommand);
+      break;
+    case 1:
+      RunCommand(kIncreaseVolumeLevelCommand);
+      break;
+    case 2:
+      RunCommand(kDecreaseVolumeLevelCommand);
+      break;
+    default:
+      DLOG(ERROR) << "SystemKeyEventListener: Unexpected message "
+                  << message.param(0)
+                  << " received";
+  }
+}
+
+void SystemKeyEventListener::RunCommand(std::string command) {
+  if (command.empty())
+    return;
+  command += " &";
+  DLOG(INFO) << "Running command \"" << command << "\"";
+  if (system(command.c_str()) < 0)
+    LOG(WARNING) << "Got error while running \"" << command << "\"";
+}
+
+}  // namespace chromeos
+
diff --git a/chrome/browser/chromeos/system_key_event_listener.h b/chrome/browser/chromeos/system_key_event_listener.h
new file mode 100644
index 0000000..9814483
--- /dev/null
+++ b/chrome/browser/chromeos/system_key_event_listener.h
@@ -0,0 +1,41 @@
+// Copyright (c) 2010 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_CHROMEOS_SYSTEM_KEY_EVENT_LISTENER_H_
+#define CHROME_BROWSER_CHROMEOS_SYSTEM_KEY_EVENT_LISTENER_H_
+
+#include <gtk/gtk.h>
+
+#include <string>
+
+#include "base/singleton.h"
+#include "chrome/browser/chromeos/wm_message_listener.h"
+
+namespace chromeos {
+
+class SystemKeyEventListener : public WmMessageListener::Observer {
+ public:
+  static SystemKeyEventListener* instance();
+
+  // WmMessageListener::Observer:
+  virtual void ProcessWmMessage(const WmIpc::Message& message,
+                                GdkWindow* window);
+
+ private:
+  // Defines the delete on exit Singleton traits we like.  Best to have this
+  // and const/dest private as recommended for Singletons.
+  friend struct DefaultSingletonTraits<SystemKeyEventListener>;
+
+  SystemKeyEventListener();
+  virtual ~SystemKeyEventListener();
+
+  void RunCommand(std::string command);
+
+  DISALLOW_COPY_AND_ASSIGN(SystemKeyEventListener);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_SYSTEM_KEY_EVENT_LISTENER_H_
+