Fix Biggest Memory leaks on Browser application

Working on Issue 31125 (http://code.google.com/p/android/issues/detail?id=31125):
* Enhance bitmap management (add recycle() functions when necessary)
* Enhance mTabViews management on NavScreen class (add remove() function
  when necessary).

Change-Id: I544620484f4ad52e02e4d3f4336a1f007bbdc8fb
Author: Sebastien MICHEL <sebastien.michel@intel.com
Signed-off-by: Xiaokang Qin <xiaokang.qin@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 56189
TOMBSTONE in com.android.browser (- android_atomic_inc+11)

there are race condition in save history webpage, at the same time,
browser destory the tab and webview, so we synchronized the tab to
resolve conflict.

Change-Id: Ib30a1215023542440e39251e8e0cd587db0ee11e
Author: binx.xu <binx.xu@intel.com>
Signed-off-by: Xiaokang Qin <xiaokang.qin@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 62273
Browser hang when playing video in popup window

The function "onShowCustomView" in WebChromeClient of subwebview is
not implemented, and makes the fullscreen layout can't be set. Here
we call main webview's onShowCustomView.

Change-Id: I576e017be61bca0775b5cc897f35092a63c6dca7
Author: weiweix.ji <weiweix.ji@intel.com>
Signed-off-by: Xiaokang Qin <xiaokang.qin@intel.com>
Signed-off-by: Bruce Beare <bruce.j.beare@intel.com>
Signed-off-by: Jack Ren <jack.ren@intel.com>
Author-tracking-BZ: 51736