Fix several squashing layer positioning bugs

This patch cleans up the squashingLayer positioning code a bit,
and fixes four issues: (1) The fixed-position constraint was
being applied to the squashingContainmentLayer instead of the
layer below it, (2) It's not correct to position the
squashingLayer with respect to the main GraphicsLayer of the
CompositedLayerMapping when the main GraphicsLayer is fixed
position, (3) When a layer pops out of a squashed layer, a
repaint needs to be issued correctly to the new repaint
container, and (4) the positioning of the squashingLayer was
incorrectly including some local positioning junk needed by
m_graphicsLayer that should not be included in the squashingLayer
position.

This patch is a merge of two other patches that are already
reviewed and approved:
https://codereview.chromium.org/108723005/
https://codereview.chromium.org/132363003/

TBR=vollick@chromium.org
BUG=328142

Review URL: https://codereview.chromium.org/128783006

git-svn-id: svn://svn.chromium.org/blink/trunk@164869 bbb929c8-8fbe-4397-9dbb-9b2b20218538
[Android WebView] Fix non-wide viewport handling code after r157293

For pages lacking <meta viewport>, page scale boundaries passed to
PageScaleConstraintsSet::adjustForAndroidWebViewQuirks will be [-1, -1],
not [0.25, 5] as we used to.

BUG=332931

Review URL: https://codereview.chromium.org/131883003

git-svn-id: svn://svn.chromium.org/blink/trunk@164870 bbb929c8-8fbe-4397-9dbb-9b2b20218538
DevTools: Fix CSS syntax errors in layersPanel.css and sourcesView.css

TBR=vsevik
NOTRY=true

Review URL: https://codereview.chromium.org/133823002

git-svn-id: svn://svn.chromium.org/blink/trunk@164871 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Reduce viewport arguments parsing noise in the DevTools console

The "minimal-ui" argument is ignored, the other parsing errors
have been transformed into warnings.

R=kenneth.r.christiansen@intel.com, pfeldman@chromium.org
BUG=332794

Review URL: https://codereview.chromium.org/133673002

git-svn-id: svn://svn.chromium.org/blink/trunk@164872 bbb929c8-8fbe-4397-9dbb-9b2b20218538
Simplify RenderLayer::shouldBeSelfPaintingLayer

The function has evolved past the point where anyone know what
it does anymore. This change aligns the self-painting layer concept
with the original intent: it was used as a performance optimization
as overflow-only RenderLayers can be painted by their RenderObject
without the need for the heavy RenderLayer painting machinery.

The new meaning is a simplification but could remove the optimization
for obscure corner cases. I think it's a fine trade-off as it is now
a concept people can understand.

Review URL: https://codereview.chromium.org/125043002

git-svn-id: svn://svn.chromium.org/blink/trunk@164873 bbb929c8-8fbe-4397-9dbb-9b2b20218538