HRTFDatabaseLoader needs to acquire a lock when accessing m_hrtfDatabase

Currently HRTFDatabaseLoader::m_threadLock is acquired when accessing
m_databaseLoaderThread, but the lock is not needed because m_databaseLoaderThread
is not accessed by multiple threads.

What we need to protect is not m_databaseLoaderThread but m_hrtfDatabase,
which is accessed by multiple threads. This CL makes the fix.

BUG=415305

Review URL: https://codereview.chromium.org/666213003

git-svn-id: svn://svn.chromium.org/blink/trunk@184166 bbb929c8-8fbe-4397-9dbb-9b2b20218538
SVGElement::parseAttribute resolves property via property map (Step 2.6)

SVGAnimatedOrder is introduced to handle parse errors for SVGFEConvolveMatrixElement's orderAttr in setBaseValueToString.

This is to replace the existing |SVGElement::parseAttribute| implementation,
but as there are many callers, we would like to proceed this incrementally.
a) Introduce |SVGElement::parseAttributeNew| *LANDED*
b) Convert all overrides |SVGElement::parseAttribute| to
   a |parseAttributeNew| call. <-- This patch
c) Replace existing |parseAttribute| with |parseAttributeNew|, and remove all
   overrides simply calling |parseAttributeNew|

This patch is (b).

BUG=397902

Review URL: https://codereview.chromium.org/668113003

git-svn-id: svn://svn.chromium.org/blink/trunk@184167 bbb929c8-8fbe-4397-9dbb-9b2b20218538