Remove Shadow DOM V0, Custom Element V0 and HTML Imports

This patch removes Shadow DOM V0, Custom Element V0 (CEv0) and HTML Imports.
Intent to Deprecate and Remove: http://bit.ly/2RGHe3x

Bug: 911943
Change-Id: I1baa906e019e0f59331c1fb590eccbc38a482fec
Reviewed-on: https://chromium-review.googlesource.com/c/1481130Reviewed-by: Hayato Ito <hayato@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Yoichi Osato <yoichio@chromium.org>
Cr-Commit-Position: refs/heads/master@{#636728}

third_party/blink/renderer/platform/runtime_enabled_features.json5

@@ -384,7 +384,7 @@
     {
       name: "CustomElementsV0",
       origin_trial_feature_name: "WebComponentsV0",
-      status: "stable",
+      status: "test",
     },
     {
       name: "CustomUserTiming",
@@ -610,7 +610,7 @@
     {
       name: "HTMLImports",
       origin_trial_feature_name: "WebComponentsV0",
-      status: "stable",
+      status: "test",
     },
     // Allow import only chrome internal resources.
     {
@@ -1268,7 +1268,7 @@
     {
       name: "ShadowDOMV0",
       origin_trial_feature_name: "WebComponentsV0",
-      status: "stable",
+      status: "test",
     },
     {
       name: "ShadowPiercingDescendantCombinator",

third_party/blink/web_tests/virtual/stable/webexposed/custom-elements-expected.txt

+CONSOLE WARNING: :unresolved pseudo selector is deprecated and will be removed in M73, around March 2019. Please use :not(:defined) instead. See https://www.chromestatus.com/features/4642138092470272 for more details.
+Tests basic web-exposure of Custom Elements
+
+On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
+
+Document.prototype.hasOwnProperty("registerElement")
+false
+
+
+typeof Document.prototype.registerElement
+undefined
+
+
+document.createElement("x-a") instanceof HTMLUnknownElement
+false
+
+
+document.querySelector(":unresolved")
+[object HTMLDivElement]
+
+
+span.getAttribute("is")
+type-extension
+
+
+PASS window.customElements.define("a-a", A, {extends: "b"}) did not throw exception.
+PASS successfullyParsed is true
+
+TEST COMPLETE
+

third_party/blink/web_tests/virtual/stable/webexposed/element-instance-property-listing-expected.txt

@@ -53,7 +53,6 @@ namespace http://www.w3.org/1999/xhtml
     property computedStyleMap
     property contains
     property contentEditable
-    property createShadowRoot
     property dataset
     property dir
     property dispatchEvent
@@ -68,7 +67,6 @@ namespace http://www.w3.org/1999/xhtml
     property getAttributeNodeNS
     property getBoundingClientRect
     property getClientRects
-    property getDestinationInsertionPoints
     property getElementsByClassName
     property getElementsByTagName
     property getElementsByTagNameNS
@@ -691,7 +689,6 @@ html element link
     property hreflang
     property imageSizes
     property imageSrcset
-    property import
     property integrity
     property media
     property referrerPolicy
@@ -1156,7 +1153,6 @@ namespace http://www.w3.org/2000/svg
     property compareDocumentPosition
     property computedStyleMap
     property contains
-    property createShadowRoot
     property dataset
     property dispatchEvent
     property firstChild
@@ -1169,7 +1165,6 @@ namespace http://www.w3.org/2000/svg
     property getAttributeNodeNS
     property getBoundingClientRect
     property getClientRects
-    property getDestinationInsertionPoints
     property getElementsByClassName
     property getElementsByTagName
     property getElementsByTagNameNS

third_party/blink/web_tests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -1365,7 +1365,6 @@ interface Document : Node
     method queryCommandValue
     method querySelector
     method querySelectorAll
-    method registerElement
     method releaseEvents
     method webkitCancelFullScreen
     method webkitExitFullscreen
@@ -1566,7 +1565,6 @@ interface Element : Node
     method closest
     method computedStyleMap
     method constructor
-    method createShadowRoot
     method getAttribute
     method getAttributeNS
     method getAttributeNames
@@ -1574,7 +1572,6 @@ interface Element : Node
     method getAttributeNodeNS
     method getBoundingClientRect
     method getClientRects
-    method getDestinationInsertionPoints
     method getElementsByClassName
     method getElementsByTagName
     method getElementsByTagNameNS
@@ -2691,7 +2688,6 @@ interface HTMLLinkElement : HTMLElement
     getter hreflang
     getter imageSizes
     getter imageSrcset
-    getter import
     getter integrity
     getter media
     getter referrerPolicy
@@ -6584,7 +6580,6 @@ interface Text : CharacterData
     getter assignedSlot
     getter wholeText
     method constructor
-    method getDestinationInsertionPoints
     method splitText
 interface TextDecoder
     attribute @@toStringTag