Rename GDataCache* to DriveCache*

Rename GDataCache* to DriveCache*

In this CL, folloing files are renamed:

* gdata_cache.{h,cc} have been renamed to drive_cache.{h,cc}
* gdata_cache_unittest.cc has been renamed to drive_cache_unittest.cc
* gdata_cache_metadata_unittest.cc has been renamed drive_cache_metadata_unittest.cc
* gdata_cache_metadata.{h,cc} have been renamed to drive_cache.{h,cc}
* mock_gdata_cache_observer.{h,cc} have been renamed to mock_drive_cache_observer.{h,cc}

All symbols including "GDataCache" are renamed to "DriveCache",
notably:

* class GDataCache has been renamed to DriveCache
* class GDataCacheMetadata has been renamed DriveCacheMetadata

These changes are almost mechanical and should not break anything.

Note: The filepath literal kGDataCacheDirname ("Gcache") is
renamed to kDriveCacheDirname, but the directory name
("GCache") still remain same. 

BUG=137151
TEST=pass all existing tests
TBR=satorux@chromium.org, ben@chromium.org

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=152774

[kochi, 2012-08-22 07:09:34]

Hi Kazuhiro,

Could you review this?
Thanks!

[kinaba, 2012-08-22 07:16:21]

lgtm

[kochi, 2012-08-22 16:04:51]

Added TBR=.

Satoru, could you check chromeos/extensions and ui/webui/chromeos?
Ben, could you review *.gypi?

[Ben Goodger (Google), 2012-08-22 16:06:32]

gyp lgtm