[iOS] Reenable OverscrollActions tests on device

The tests now pass after
https://chromium-review.googlesource.com/c/chromium/src/+/2446782. See
below for a hypothesis on the root causes.

The root cause of the issue is a unclear, but seems to be as follows:
The overscroll state is supposed to change twice, once to
STARTED_PULLING after the |-scrollViewDidScroll| call, and once to
ACTION_READY after the contentOffset is updated. This happens
on simulator, but on device, the first change actually causes the
overscroll state to change to NO_PULL_STARTED.

This seems to be because on device, the initial contentOffset is 0,
while on simulator, it is ~ -2.46E-314, which compares less than 0 in
|OverscrollActionsController scrollViewDidScroll|. To fix this, I
changed the content offset in the test manually to a small number less
than 0.

Bug: 944599
Change-Id: I0d062e6ab9d20aca0b85810375b0081186fef48a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2390381
Commit-Queue: Robbie Gibson <rkgibson@google.com>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Reviewed-by: Mohammad Refaat <mrefaat@chromium.org>
Cr-Commit-Position: refs/heads/master@{#820216}

ios/chrome/browser/overscroll_actions/overscroll_actions_tab_helper_unittest.mm

@@ -86,13 +86,7 @@ class OverscrollActionsTabHelperTest : public PlatformTest {
 
 // Tests that OverscrollActionsControllerDelegate is set correctly and triggered
 // When there is a view pull.
-// TODO(crbug.com/944599): Fails on device.
-#if TARGET_IPHONE_SIMULATOR
-#define MAYBE_TestDelegateTrigger TestDelegateTrigger
-#else
-#define MAYBE_TestDelegateTrigger DISABLED_TestDelegateTrigger
-#endif
-TEST_F(OverscrollActionsTabHelperTest, MAYBE_TestDelegateTrigger) {
+TEST_F(OverscrollActionsTabHelperTest, TestDelegateTrigger) {
   web_state_.SetBrowserState(browser_state_.get());
   overscroll_tab_helper()->SetDelegate(overscroll_delegate_);
   // Start pull for page refresh action.
@@ -108,13 +102,7 @@ TEST_F(OverscrollActionsTabHelperTest, MAYBE_TestDelegateTrigger) {
 
 // Tests that overscrolls actions view style is set correctly, for regular
 // browsing browser state.
-// TODO(crbug.com/944599): Fails on device.
-#if TARGET_IPHONE_SIMULATOR
-#define MAYBE_TestRegularBrowserStateStyle TestRegularBrowserStateStyle
-#else
-#define MAYBE_TestRegularBrowserStateStyle DISABLED_TestRegularBrowserStateStyle
-#endif
-TEST_F(OverscrollActionsTabHelperTest, MAYBE_TestRegularBrowserStateStyle) {
+TEST_F(OverscrollActionsTabHelperTest, TestRegularBrowserStateStyle) {
   web_state_.SetBrowserState(browser_state_.get());
   overscroll_tab_helper()->SetDelegate(overscroll_delegate_);
   SimulatePullForRefreshAction();
@@ -125,16 +113,7 @@ TEST_F(OverscrollActionsTabHelperTest, MAYBE_TestRegularBrowserStateStyle) {
 
 // Tests that overscrolls actions view style is set correctly, for off the
 // record browser state.
-// TODO(crbug.com/944599): Fails on device.
-#if TARGET_IPHONE_SIMULATOR
-#define MAYBE_TestOffTheRecordBrowserStateStyle \
-  TestOffTheRecordBrowserStateStyle
-#else
-#define MAYBE_TestOffTheRecordBrowserStateStyle \
-  DISABLED_TestOffTheRecordBrowserStateStyle
-#endif
-TEST_F(OverscrollActionsTabHelperTest,
-       MAYBE_TestOffTheRecordBrowserStateStyle) {
+TEST_F(OverscrollActionsTabHelperTest, TestOffTheRecordBrowserStateStyle) {
   web_state_.SetBrowserState(
       browser_state_->GetOffTheRecordChromeBrowserState());
   overscroll_tab_helper()->SetDelegate(overscroll_delegate_);