WTF::notFound looks too much like a local variable.

I discovered this as part of attempting to deploy -Wshadow.
There was one place (HashMap.h) where we had a notFound local.

Changing notFound to kNotFound also made it look pretty in my editor.

This sorta seems like a silly change, but I do believe it will help
code readability.  I think it was a mistake to have a global constant
beginging with a lowercase letter in the first place.

BUG=294205

Review URL: https://chromiumcodereview.appspot.com/23464095

git-svn-id: svn://svn.chromium.org/blink/trunk@158058 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add code style check error for using static_cast instead of toFoo function.

We are migrating to new syntax of calling toFoo for any type of static_cast we do on Foo objects. We are adding to more and more classes toFoo helper functions, so we should ensure that the added helpers are actually *used* in the code. Currently, there is no enforcement on the same and through this change we are adding that style check which will fail any patch upload if we are not following toFoo style (if toFoo exists). As part of testing,  executed check-webkit-style on all source files which still have static_cast<Foo*> code syntax. The script throws style error if we are using static_cast though we already have toFoo helper function. If toFoo is not yet defined, it doesn't throw any error right now (should that be changed?) 

BUG=None

TEST=none; no behavior change;

Review URL: https://chromiumcodereview.appspot.com/23654034

git-svn-id: svn://svn.chromium.org/blink/trunk@158059 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix handling of top margin on float with shape-outside

When a float has shape outside, the top margin should be treated as if there is
no shape there, so inline content should be allowed to flow into that space.
This patch fixes two issues:

1) If the top margin is the same as the line height, a line should be able to
fit into the margin. Before this patch, that line was being treated as if it
intersected with the shape.

2) The shape should be positioned (x, y) relative to the box sizing box of the
float. While the x coordinate was being treated properly, the y coordinate was
relative to the top of the margin box. This patch fixes this behavior.

This patch also includes a simple test for right and left margins, as I wrote
that test and then discovered the problems listed above.

This patch also removes an unused override of the lineOverlapsShapeBounds
method.

BUG=260357

Review URL: https://chromiumcodereview.appspot.com/23965006

git-svn-id: svn://svn.chromium.org/blink/trunk@158060 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Fix unitialized m_cachedHorizontalWritingMode in FloatingObjects.cpp. Failing valgrind layout.

BUG=

Review URL: https://chromiumcodereview.appspot.com/23855009

git-svn-id: svn://svn.chromium.org/blink/trunk@158061 bbb929c8-8fbe-4397-9dbb-9b2b20218538