Fix the crash issue when accessing geolocation APIs.

Implement a dummy AccessTokenStore to avoid returning NULL pointer.

Initialize the geolocation browser test with simple case which uses
navigator.geolocation.getCurrentPosition API.

BUG=https://github.com/otcshare/cameo/issues/34
TEST=cameo_browsertest --gtest_filter=CameoRuntimeTest.LoadGeolocationPage
Merge pull request #35 from huningxin/geolocation_fix

Fix the crash issue when accessing geolocation APIs.
Merge pull request #71 from hmin/re-enable-test

Re-enable RemoteDebugging browser test
geolocation test: set the timeout to avoid browser test fails

When geolocation network provider is not reachable, geolocation
getCurrentPosition takes long time to timeout. It might get browser test to
timeout (30 secs) first and mark failure.

Set the getCurrentPosition timeout as 5 secs to avoid this to happen.
Fix two potential failure in fetch_deps.py

1. Set timeout to 30 minutes for step git checkout in src/
2. Skip checkout step if the specified branch already exist in src/
Implement way to add ignore paths when checking out chromium

By default, the paths recommended to be ignored at
http://dev.chromium.org/developers/how-tos/get-the-code will be set
with None in the gclient config file for checking out chromium.

Developers can speicify environment variable CAMEO_SYNC_IGNORE to
override the ignore list. Split multiple paths with ':' or ';'
Add depot_tools to PYTHONPATH for pylint

Otherwise, pylint will fail on trybot.
Using pylint.bat on Windows
Upgrade chromium base to 28.0.1500.36
Merge pull request #78 from wang16/fetch_deps

Enhance fetch_deps.py
Merge pull request #79 from wang16/rebase_1500

[Place Holder] Upgrade chromium base to 28.0.1500.36
Small clean up: remove unnecessary includes
Merge pull request #86 from cmarcelo/cleanup

Small clean up: remove unnecessary includes
Support using favicon as app icon

This patch is to make native app window use favicon as its window icon.
Both ICO and PNG file are supported for both Windows and Gtk.

The following example HTML code shows how to use favicon meta tag:

<html>
<head>
<link rel="icon" href="16x16.png">
</head>
...
</html>

As a result, the icon 16x16.png will be used as the icon showed on both
window title bar and task bar.

Known issues:
o [GTK] App icon of GtkWindow can not be updated to the expected favicon. The
  reason is, gtk_window_set_icon has no any effect after gtk_window_show
  calling. The same issue also exists in Google Chrome.

o [Windows 7] The icon won't show on title bar if using custom frame. It
  could be addressed by forcing NativeWidgetWin to use native frame.

BUG=https://github.com/otcshare/cameo/issues/72
TEST=CameoRuntimeTest.FaviconTest_ICO
TEST=CameoRuntimeTest.FaviconTest_PNG
Merge pull request #83 from hmin/app-icon

Support using favicon as app icon
Differentiate app by app ID on Windows

Make icons of different apps show in different group in Windows7
taskbar.

BUG=https://github.com/otcshare/cameo/issues/77
TEST=cameo_browsertest --gtest_filter=CameoTaskbarGroupingTest.*
[Tools/Lint] Ignore Header guard check for IPC messages

IPC messages' header will be include multiple times with
different macros, so they don't need header guard.
[Tools/Lint] Remove workaround of rename .git of cameo

The origin workaround is for header guard check for cameo
project, it rename the .git directory to let lint script
think the root project is chromium.

New solution is to override the function in depot_tools
to make it handle cameo's case correctly.
Merge pull request #89 from wang16/fetch_deps

Override some behavior of cpplint in depot_tools for cameo specific
Add Cameo extension subsystem

The Cameo extension subsystem is a set of classes that can be used by
Browser and Renderer processes to run native code that respects a
certain interface.

The interface is minimal and exposes message passing between the
extension and the JS code running in the Renderer process. Extensions
currently are run in the Browser process, either on the FILE or UI
threads.

A more detailed design document is available at
https://github.com/otcshare/cameo/wiki/Message-passing-extensions

BUG=https://github.com/otcshare/cameo/issues/65