[root layer scrolls] Rebaseline devtools layer tree and compositing test

layer-tree-model.js:
This test dumps the layer tree and associated elements. With root
layer scrolling (RLS), the layers are associated with different
elements (e.g., the iframe scrolling contents layer is "#document"
instead of "iframe#frame") and there are a different number of
layers, but the test passes otherwise.

layer-compositing-reasons.js:
This test dumps the compositing reasons for all layers, directly from
the GraphicsLayer object. With RLS, the root layer has two additional
reasons: overflowScrollingTouch and rootScroller.

Bug: 781428
Change-Id: Ibc1e654474c96d2dd8dfdfc01ec52046989c30cb
Cq-Include-Trybots: master.tryserver.chromium.linux:linux_layout_tests_root_layer_scrolls
Reviewed-on: https://chromium-review.googlesource.com/804620
Commit-Queue: Philip Rogers <pdr@chromium.org>
Reviewed-by: Stefan Zager <szager@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521914}

third_party/WebKit/LayoutTests/FlagExpectations/root-layer-scrolls

@@ -23,8 +23,6 @@ crbug.com/417782 [ Linux Mac ] fast/spatial-navigation/snav-media-elements.html
 crbug.com/417782 [ Linux ] fast/spatial-navigation/snav-unit-overflow-and-scroll-in-direction.html [ Failure ]
 crbug.com/417782 html/dialog/form-method-dialog.html [ Crash ]
 crbug.com/417782 http/tests/devtools/device-mode/default-background-color.html [ Failure ]
-crbug.com/417782 http/tests/devtools/layers/layer-compositing-reasons.js [ Failure ]
-crbug.com/417782 http/tests/devtools/layers/layer-tree-model.js [ Failure ]
 crbug.com/417782 http/tests/devtools/tracing/scroll-invalidations.js [ Failure ]
 crbug.com/417782 http/tests/devtools/tracing/timeline-paint/layer-tree.js [ Failure ]
 crbug.com/417782 http/tests/devtools/tracing/timeline-paint/timeline-paint-with-layout-invalidations-on-deleted-node.js [ Failure ]

third_party/WebKit/LayoutTests/flag-specific/root-layer-scrolls/http/tests/devtools/layers/layer-compositing-reasons-expected.txt

+Tests layer compositing reasons in Layers Panel
+Compositing reasons for #document: overflowScrollingTouch,root,rootScroller
+Compositing reasons for div#transform3d: assumedOverlap,inlineTransform,transform3D
+Compositing reasons for div#transform3d-individual: assumedOverlap,inlineTransform,transform3D
+Compositing reasons for iframe#iframe: iFrame
+Compositing reasons for div#backface-visibility: assumedOverlap,backfaceVisibilityHidden
+Compositing reasons for div#animation: activeAnimation,assumedOverlap
+Compositing reasons for div#animation-individual: activeAnimation,assumedOverlap
+Compositing reasons for div#transformWithCompositedDescendants: assumedOverlap,inlineTransform,transformWithCompositedDescendants
+Compositing reasons for div#transformWithCompositedDescendants-individual: assumedOverlap,inlineTransform,transformWithCompositedDescendants
+Compositing reasons for div#opacityWithCompositedDescendants: assumedOverlap,opacityWithCompositedDescendants
+Compositing reasons for div#reflectionWithCompositedDescendants: assumedOverlap,filterWithCompositedDescendants,reflectionWithCompositedDescendants
+Compositing reasons for div#perspective: assumedOverlap,perspectiveWith3DDescendants
+Compositing reasons for div#preserve3d: assumedOverlap,preserve3DWith3DDescendants
+

third_party/WebKit/LayoutTests/flag-specific/root-layer-scrolls/http/tests/devtools/layers/layer-tree-model-expected.txt

+Tests general layer tree model functionality
+Initial layer tree
+#document (5)
+    #document (6)
+        #document (7)
+            iframe#frame (8)
+                #document 200x200 (9)
+                    #document 200x200 (10)
+                        div#subframe1 80x80 (11)
+            div#a 200x200 (8)
+                div#b1 100x150 (9)
+                div#b2 110x140 (9)
+                    div#c 90x100 (10)
+                div#b3 110x140 (9)
+Updated layer tree
+#document (5)
+    #document (6)
+        #document (7)
+            iframe#frame (8)
+                #document 200x200 (9)
+                    #document 200x200 (10)
+                        div#subframe1 80x80 (11)
+            div#a 200x200 (8)
+                div#b2 110x140 (9)
+                    div#c 90x100 (10)
+                        div#b1 100x150
+                div#b4 0x0
+Updated layer geometry
+#document (5)
+    #document (6)
+        #document (7)
+            iframe#frame (8)
+                #document 200x200 (9)
+                    #document 200x200 (10)
+                        div#subframe1 80x80 (11)
+            div#a 200x200 (8)
+                div#b2 110x140 (9)
+                    div#c 90x80 (10)
+                        div#b1 100x150
+                div#b4 0x0
+

third_party/WebKit/LayoutTests/http/tests/devtools/layers/layer-tree-model.js

@@ -16,7 +16,8 @@
         height: 200px;
       }
       </style>
-      <div id="a" style="width: 200px; height: 200px" class="layer">    <div class="layer" id="b1" style="width: 150px; height: 100px"></div>
+      <div id="a" style="width: 200px; height: 200px" class="layer">
+          <div class="layer" id="b1" style="width: 150px; height: 100px"></div>
           <div id="b2" class="layer" style="width: 140px; height: 110px">
               <div id="c" class="layer" style="width: 100px; height: 90px"></div>
           </div>