Extend flakiness of overflow/overflow-positioning.html.

Sadly, it's flaky occasionally everywhere.

BUG=245630
TBR=enne

Review URL: https://codereview.chromium.org/47923004

git-svn-id: svn://svn.chromium.org/blink/trunk@160731 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Add explicit API to clear backing store and canvas.

Once most resizes start happening asynchronously, the forcing of
size at the beginning of each test will become the odd man out.
This means that we can't hook into setWindowRect anymore and
instead need a special API, thereby pronounced didForceResize.

BUG=309760
R=eseidel, jochen, tony

Review URL: https://codereview.chromium.org/47953002

git-svn-id: svn://svn.chromium.org/blink/trunk@160732 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Element should not use confusingAndOftenMisusedAttached

Instead introduce Node::inActiveDocument() and use that. To do this I had
to rename a method of the same name on HTMLMediaElement. All callers in
Element.cpp that were checking attached really just want to know if the
element is in an active document and participating in recalcStyle.

Review URL: https://codereview.chromium.org/26270004

git-svn-id: svn://svn.chromium.org/blink/trunk@160733 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Move InspectorBackendDispatcher::commandNames array from .data to .rodata section

Move InspectorBackendDispatcher::commandNames array from .data to .rodata section
by getting rid of the pointers / relocations and using 1 single const char array
for all command names. An index array was introduced to store the index of each
command name in the char array.

This effectively moves commandNames array from .data to .rodata:
- Before: (.rodata: 8788 bytes / .data: 880 bytes)
- After: (.rodata: 9669 bytes / .data: 0 bytes)

The binary size is up 1 byte but we moved 880 bytes to shareable readonly memory,
thus potentially reducing RAM usage on Android a bit.

This change also reduces the number of relocations by ~220 according to relinfo,
which decreases the load time of the library.

BUG=249746

Review URL: https://codereview.chromium.org/48743004

git-svn-id: svn://svn.chromium.org/blink/trunk@160734 bbb929c8-8fbe-4397-9dbb-9b2b20218538