XMLTreeViewer should be created only in the XML viewer mode

Moving XMLTreeViewer::hasNoStyleInformation to be static inline method in XMLDocumentParser.cpp as
it should not be the responsibility of XMLTreeViewer.

R=abarth

Review URL: https://chromiumcodereview.appspot.com/22150003

git-svn-id: svn://svn.chromium.org/blink/trunk@155521 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Use base::FilePath::BaseName() to get base name in Blink

rather than having platform-specific implementation in Blink code.

Chrome side patch: https://codereview.chromium.org/21733003/

BUG=267341
TEST=green bots

Review URL: https://chromiumcodereview.appspot.com/21733002

git-svn-id: svn://svn.chromium.org/blink/trunk@155522 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove unused variable in InspectorFrontendHostStub.

BUG=

Review URL: https://chromiumcodereview.appspot.com/22166002

git-svn-id: svn://svn.chromium.org/blink/trunk@155523 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Remove 'String::append' from 'Source/core/accessibility/AccessibilityNodeObject.cpp'.

Replaced with StringBuilder for (marginally) better performance.

BUG=268281

Review URL: https://chromiumcodereview.appspot.com/22042003

git-svn-id: svn://svn.chromium.org/blink/trunk@155524 bbb929c8-8fbe-4397-9dbb-9b2b20218538