android_webview: stop using system ashmem.

To support unbundled updates we need to stop depending on system
libraries. Disable using the system ashmem APIs in libcutils and instead
link Chromium's copy, and remove support for using the version in
libcutils as there are no other users.

This increases binary size by <1KB.

BUG=409851

Review URL: https://codereview.chromium.org/550213002

Cr-Commit-Position: refs/heads/master@{#293916}

android_webview/tools/known_issues.py

@@ -52,7 +52,6 @@ KNOWN_INCOMPATIBLE = {
 
         # Code we don't want to build/include by accident from the main chromium
         # src/ directory.
-        'third_party/ashmem/*.[ch]',
         'third_party/libjpeg/*.[ch]',
     ],
     'third_party/icu': [

third_party/ashmem/BUILD.gn

@@ -4,19 +4,9 @@
 
 assert(is_android)
 
-import("//build/config/android/config.gni")
-
-if (is_android_webview_build) {
-  # WebView build uses the Android system version of ashmem to avoid linking
-  # problems.
-  group("ashmem") {
-    assert(false, "Implement system ashmem for webview build")
-  }
-} else {
-  source_set("ashmem") {
-    sources = [
-      "ashmem.h",
-      "ashmem-dev.c",
-    ]
-  }
+source_set("ashmem") {
+  sources = [
+    "ashmem.h",
+    "ashmem-dev.c",
+  ]
 }

third_party/ashmem/ashmem.gyp

@@ -6,33 +6,10 @@
   'targets': [
     {
       'target_name': 'ashmem',
-      'conditions': [
-        ['android_webview_build==1', {
-          # WebView must use the Android system version of ashmem to avoid
-          # linking problems.
-          'type': 'none',
-          'variables': {
-            'headers_root_path': '.',
-            'header_filenames': [ 'ashmem.h' ],
-            'shim_generator_additional_args': [
-              '--prefix', 'cutils/',
-            ],
-          },
-          'includes': [
-            '../../build/shim_headers.gypi',
-          ],
-          'link_settings': {
-            'libraries': [
-              '-lcutils',
-            ],
-          },
-        }, {
-          'type': 'static_library',
-          'sources': [
-            'ashmem.h',
-            'ashmem-dev.c'
-          ],
-        }],
+      'type': 'static_library',
+      'sources': [
+        'ashmem.h',
+        'ashmem-dev.c'
       ],
     },
   ],