Clean up Editor class

This patch cleans Editor class up by
- removing unused member functions rangeForPoint(), removedAnchor(), setRemovedAnchor(), simplifyMarkup().
- expanding isContinuousSpellCheckingEnabled() and removes it
- making rangeOfString() private

BUG=n/a
TEST=n/a; no behavior changes

Review URL: https://codereview.chromium.org/63363009

git-svn-id: svn://svn.chromium.org/blink/trunk@162328 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Do not schedule font loading if already started

r162179 (reverted in r162249) caused timeouts on some layout tests where
onload handler was not invoked. That happens when
FontLoader::beginLoadTimerFired does not start any font loading
because all fonts in m_fontsToBeginLoading are already loading.
ResourceFetcher::decrementRequestCount makes the request count zero, but
it does not trigger the load event.

To resolve this, this patch makes FontLoader::addFontToBeginLoading
skip fontResource if it's already loading or loaded.

BUG=246492,320732
TEST=fast/frames/seamless/seamless-nested-crash.html,http/tests/misc/acid3.html

Review URL: https://codereview.chromium.org/75983002

git-svn-id: svn://svn.chromium.org/blink/trunk@162329 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2D Canvas: Refactor code re-attempting to allocate an imageBuffer.

m_hasCreatedImageBuffer prevents HTMLCanvasElement::buffer()
from continuously re-attempting to allocate an imageBuffer after the first
attempt failed. This has huge implications for performance in low memory
conditions.

m_hasCreatedImageBuffer was misnamed, so it ended-up being misused in several
places.

This CL renames m_hasCreatedImageBuffer to m_didFailToCreateImageBuffer, and
then m_didFailToCreateImageBuffer is used in only relevant places.

TEST=fast/canvas/canvas-extremely-large-dimensions.html

Review URL: https://codereview.chromium.org/44253005

git-svn-id: svn://svn.chromium.org/blink/trunk@162330 bbb929c8-8fbe-4397-9dbb-9b2b20218538