https://bugs.webkit.org/show_bug.cgi?id=122291

Reviewed by Timothy Hatcher.

Source/WebCore:

Tests: inspector/elements/highlight-regions-flow-horiz-bt.html
       inspector/elements/highlight-regions-flow-transform-horiz-bt.html
       inspector/elements/highlight-regions-flow-transform-vert-lr.html
       inspector/elements/highlight-regions-flow-transform-vert-rl.html
       inspector/elements/highlight-regions-flow-transform.html
       inspector/elements/highlight-regions-flow-vert-lr.html
       inspector/elements/highlight-regions-flow-vert-rl.html
       inspector/elements/highlight-regions-flow.html

Nodes inside a RenderFlowThread can be split across multiple regions. This patch adds the required
code to compute "fragments" for each region. Each fragment will display its own label.

There are a couple of changes:
1. The node highlight object now has a "scroll" property to hold the main view's scroll offset.
2. There's a "fragment" array to get a list of quads for each renderer fragment. Renderers outside
RenderFlowThreads will just have one fragment.
3. ElementInfo now has two more properties: "regionFlowInfo" (renamed from former flowInfo) and "contentFlowInfo".
If the renderer is a RenderRegion it will have a regionFlowInfo. If the renderer is inside a RenderFlowThread
then it will have a "contentFlowInfo".

* inspector/InspectorOverlay.cpp:
(WebCore::InspectorOverlay::getHighlight): It should now take a "region" parameter to customize the output for a specific
containing region.
(WebCore::buildObjectForHighlight):
(WebCore::buildObjectForCSSRegionContentClip): We need to know how to clip the fragments inside regions.
(WebCore::buildObjectForRendererFragments): Extracted code from buildObjectForHighlight and added
the new regions lookup code.
(WebCore::buildObjectForElementInfo): Extracted from buildObjectForHighlight.
(WebCore::InspectorOverlay::buildObjectForHighlightedNode):
(WebCore::InspectorOverlay::drawQuadHighlight):
* inspector/InspectorOverlayPage.css: There can be multiple labels on screen at once, so I've
created the #element-title-template element that we clone for each label. .element-title-container is now
holding all the .element-title elements, so that we can remove them all at once.
(.element-title-container):
(.element-title):
(#element-title-template):
(.tag-name):
(.node-id):
(.class-name):
* inspector/InspectorOverlayPage.html:
* inspector/InspectorOverlayPage.js:
(reset):
(_toggleOptionalValue):
(_createElementTitle): Creates an element populated with data read from elementInfo.
(_drawElementTitle): Added code to create more labels for multiple fragments.
(_drawRegionsHighlight):
(_drawFragmentHighlight):
(drawNodeHighlight): Consolidated the scroll property into a canvas.transform.

LayoutTests:

Added tests to check the result of the InspectorOverlay when it inspects nodes inside RenderFlowThreads.

* http/tests/inspector/elements-test.js:
* inspector/elements/highlight-regions-flow-expected.txt: Added.
* inspector/elements/highlight-regions-flow-horiz-bt-expected.txt: Added.
* inspector/elements/highlight-regions-flow-horiz-bt.html: Added.
* inspector/elements/highlight-regions-flow-transform-expected.txt: Added.
* inspector/elements/highlight-regions-flow-transform-horiz-bt-expected.txt: Added.
* inspector/elements/highlight-regions-flow-transform-horiz-bt.html: Added.
* inspector/elements/highlight-regions-flow-transform-vert-lr-expected.txt: Added.
* inspector/elements/highlight-regions-flow-transform-vert-lr.html: Added.
* inspector/elements/highlight-regions-flow-transform-vert-rl-expected.txt: Added.
* inspector/elements/highlight-regions-flow-transform-vert-rl.html: Added.
* inspector/elements/highlight-regions-flow-transform.html: Added.
* inspector/elements/highlight-regions-flow-vert-lr-expected.txt: Added.
* inspector/elements/highlight-regions-flow-vert-lr.html: Added.
* inspector/elements/highlight-regions-flow-vert-rl-expected.txt: Added.
* inspector/elements/highlight-regions-flow-vert-rl.html: Added.
* inspector/elements/highlight-regions-flow.html: Added.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@157199 268f45cc-cd09-0410-ab3c-d52691b4dbfc