Preload static strings into the AtomicStringTable

Static strings are immortal strings that are safe to use on any thread.
However, we can get confused on background threads that have AtomicStringTables
because the static strings are marked atomic but aren't in that thread's
AtomicStringTable.

In this CL, we preload the AtomicStringTable for every thread with all the
static strings. That means the static strings will be in every thread's atomic
string table, paving the way for removing thread-local event names.

R=dglazkov@chromium.org

Review URL: https://codereview.chromium.org/26009003

git-svn-id: svn://svn.chromium.org/blink/trunk@159072 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fold localizedMediaControlElementString() and localizedMediaControlElementHelpText() into AccessibilityMediaControls.cpp.

It's ok to use WebKit::Platform directly in core/accessibility/.

Also, these functions took a string argument which identified media controls. It
had no benefit in Blink and we had better use "switch (controlType())" in
accessibilityDescription() and helpText().

BUG=298020
TEST=none; no behavior changes

Review URL: https://codereview.chromium.org/26229002

git-svn-id: svn://svn.chromium.org/blink/trunk@159074 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Mark some storage/indexeddb tests as Win7 crashers

Gardening.

TBR=toyoshim@chromium.org,eseidel@chromium.org
BUG=

Review URL: https://codereview.chromium.org/26184007

git-svn-id: svn://svn.chromium.org/blink/trunk@159075 bbb929c8-8fbe-4397-9dbb-9b2b20218538