Replace [GREYConfiguration sharedInstance] with ScopedSynchronizationDisabler.

This is part of EG1 to EG2 migration, which involves moving
EarlGrey code from app-side helpers into test code.
EarlGrey2 has multiprocess architecture,
where Chrome Test and Chrome App are separate processes

Change-Id: Ib41116bb8df8c8383ad8a76460d5643560983716
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1732157
Commit-Queue: Maksym Onufriienko <monufriienko@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Cr-Commit-Position: refs/heads/master@{#683767}

ios/chrome/browser/autofill/BUILD.gn

@@ -514,6 +514,7 @@ source_set("eg_tests") {
     "//ios/chrome/app/strings",
     "//ios/chrome/browser/autofill:autofill_shared",
     "//ios/chrome/browser/ui/util",
+    "//ios/chrome/test:eg_test_support",
     "//ios/chrome/test/app:test_support",
     "//ios/chrome/test/earl_grey:test_support",
     "//ios/testing/earl_grey:earl_grey_support",

ios/chrome/browser/autofill/form_input_egtest.mm

@@ -16,6 +16,7 @@
 #import "ios/chrome/test/earl_grey/chrome_earl_grey.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
+#import "ios/chrome/test/scoped_eg_synchronization_disabler.h"
 #import "ios/web/public/deprecated/crw_js_injection_receiver.h"
 #import "ios/web/public/test/earl_grey/web_view_actions.h"
 #import "ios/web/public/test/earl_grey/web_view_matchers.h"
@@ -27,6 +28,9 @@
 #error "This file requires ARC support."
 #endif
 
+using base::test::ios::kWaitForUIElementTimeout;
+using base::test::ios::WaitUntilConditionOrTimeout;
+
 using chrome_test_util::WebViewMatcher;
 
 namespace {
@@ -55,8 +59,7 @@ void AssertElementIsFocused(const std::string& element_id) {
   ConditionBlock condition = ^{
     return base::SysNSStringToUTF8(GetFocusedElementId()) == element_id;
   };
-  GREYAssert(base::test::ios::WaitUntilConditionOrTimeout(10, condition),
-             description);
+  GREYAssert(WaitUntilConditionOrTimeout(10, condition), description);
 }
 
 }  // namespace
@@ -68,12 +71,6 @@ void AssertElementIsFocused(const std::string& element_id) {
 @implementation FormInputTestCase
 
 - (void)tearDown {
-  // |testFindDefaultFormAssistControls| disables synchronization.
-  // This makes sure it is enabled if that test has failed and did not enable it
-  // back.
-  [[GREYConfiguration sharedInstance]
-          setValue:@YES
-      forConfigKey:kGREYConfigKeySynchronizationEnabled];
   [super tearDown];
 }
 
@@ -96,9 +93,8 @@ void AssertElementIsFocused(const std::string& element_id) {
   [ChromeEarlGrey waitForWebStateContainingText:"hello!"];
 
   // Opening the keyboard from a webview blocks EarlGrey's synchronization.
-  [[GREYConfiguration sharedInstance]
-          setValue:@NO
-      forConfigKey:kGREYConfigKeySynchronizationEnabled];
+  {
+    ScopedSynchronizationDisabler disabler;
 
     // Brings up the keyboard by tapping on one of the form's field.
     [[EarlGrey selectElementWithMatcher:WebViewMatcher()]
@@ -118,7 +114,8 @@ void AssertElementIsFocused(const std::string& element_id) {
             IDS_IOS_AUTOFILL_ACCNAME_HIDE_KEYBOARD);
 
     // Wait until the keyboard's "Next" button appeared.
-  NSString* description = @"Wait for the keyboard's \"Next\" button to appear.";
+    NSString* description =
+        @"Wait for the keyboard's \"Next\" button to appear.";
     ConditionBlock condition = ^{
       NSError* error = nil;
       [[EarlGrey selectElementWithMatcher:nextButtonMatcher]
@@ -126,8 +123,7 @@ void AssertElementIsFocused(const std::string& element_id) {
                       error:&error];
       return (error == nil);
     };
-  GREYAssert(base::test::ios::WaitUntilConditionOrTimeout(
-                 base::test::ios::kWaitForUIElementTimeout, condition),
+    GREYAssert(WaitUntilConditionOrTimeout(kWaitForUIElementTimeout, condition),
                description);
     base::test::ios::SpinRunLoopWithMinDelay(base::TimeDelta::FromSeconds(1));
 
@@ -147,10 +143,7 @@ void AssertElementIsFocused(const std::string& element_id) {
     // Tap the "Close" button.
     [[EarlGrey selectElementWithMatcher:closeButtonMatcher]
         performAction:grey_tap()];
-
-  [[GREYConfiguration sharedInstance]
-          setValue:@YES
-      forConfigKey:kGREYConfigKeySynchronizationEnabled];
+  }
 }
 
 // Tests that trying to programmatically dismiss the keyboard when it isn't