Credential manager: Introduce platform interface.

This patch adds a WebCredentialManager interface that the credential
manager module will (eventually) use to call up into its embedder in
response to JavaScript API calls.

These methods don't currently do anything, and aren't actually called;
until the Chromium-side work is done, there's no reason to wire them up
to the JavaScript bindings.

BUG=400674

Review URL: https://codereview.chromium.org/456293002

git-svn-id: svn://svn.chromium.org/blink/trunk@180040 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Cleanup namespace usage in public/platform/{Web[P-W]*,linux/*}.h

- Merge multiple |namespace blink {}| blocks
- Remove unnecessary blink:: prefixes
- Make blank lines consistent

BUG=

Review URL: https://codereview.chromium.org/462843003

git-svn-id: svn://svn.chromium.org/blink/trunk@180041 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark http/tests/misc/location-replace-crossdomain.html as slow on Win XP

BUG=402801
TBR=zerny@chromium.org
NOTRY=true

Review URL: https://codereview.chromium.org/467553002

git-svn-id: svn://svn.chromium.org/blink/trunk@180042 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[CSS Grid Layout] Ignore ::first-letter pseudo-element

According to the spec the ::first-line pseudo-element do not apply to
grid containers (neither to flexboxes).

Modified RenderBlock::findFirstLetterBlock() to use isRenderBlockFlow()
instead of isFlexibleBox(). This change has been already made before in
several parts of the code, but there was one missing case here.

Fix issue in RenderBlock::updateFirstLetter() that applies to both grids
and flexboxes. Basically if the grid's or flexbox's container was
defining the ::first-line pseudo-element and the grid or flexbox itself
too, the value from the grid or flexbox was being applied to the items.
Add the proper check to avoid this.

Added two new tests for grid and modified flexbox test to cover the
issue explained above.

TEST=css3/flexbox/flexbox-ignore-container-firstLetter.html
TEST=fast/css-grid-layout/grid-container-ignore-first-letter.html
TEST=fast/css-grid-layout/grid-item-first-letter-valid.html

BUG=395788

Review URL: https://codereview.chromium.org/440233002

git-svn-id: svn://svn.chromium.org/blink/trunk@180043 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Cleanup duplicated namespace in AnimationTranslationUtil

Review URL: https://codereview.chromium.org/453393002

git-svn-id: svn://svn.chromium.org/blink/trunk@180044 bbb929c8-8fbe-4397-9dbb-9b2b20218538