Rename fieldtrial_testing_like_official_build GN flag.

This flag name is confusing.  Name it disable_fieldtrial_testing_config,
which is what it actually does.

Bug: 1154841
Change-Id: I9e3cd69a95803a397df1bb7a3ed5e47e75f46b2e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3034966
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Caitlin Fischer <caitlinfischer@google.com>
Auto-Submit: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Caitlin Fischer <caitlinfischer@google.com>
Cr-Commit-Position: refs/heads/master@{#902509}

android_webview/docs/aosp-system-integration.md

@@ -190,7 +190,7 @@ is_official_build = true
 
 # Use the default production settings for field trials, instead of the testing
 # defaults.
-fieldtrial_testing_like_official_build = true
+disable_fieldtrial_testing_config = true
 
 # WebView's efficient native library loading mechanism is not compatible with
 # component builds of Chromium.

components/variations/service/BUILD.gn

@@ -9,13 +9,11 @@ declare_args() {
   # Set to true make a build that disables activation of field trial tests
   # specified in testing/variations/fieldtrial_testing_config.json.
   # Note: this setting is ignored if is_chrome_branded.
-  # TODO(thakis): It's strange this is called "_like_official_build" but then
-  # checks is_chrome_branded, not is_official_build.
-  fieldtrial_testing_like_official_build = is_chrome_branded
+  disable_fieldtrial_testing_config = false
 }
 
 fieldtrial_testing_enabled =
-    !fieldtrial_testing_like_official_build && !is_chrome_branded
+    !disable_fieldtrial_testing_config && !is_chrome_branded
 
 buildflag_header("buildflags") {
   header = "buildflags.h"

testing/variations/README.md

@@ -14,7 +14,7 @@ sync_integration_tests). It is not used by unit test targets.
 
 > Note: Non-developer builds of Chromium (for example, non-Chrome browsers,
 > or Chromium builds provided by Linux distros) should disable the testing
-> config via the GN flag `fieldtrial_testing_like_official_build=true`.
+> config via the GN flag `disable_fieldtrial_testing_config=true`.
 
 ## Config File Format