Use EXPECT_EQ directly instead of EXPECT_STREQ in blink

As the first step to deprecate WTF::CString, the bug has suggested replacing
EXPECT_STREQ with EXPECT_EQ. Although previous CLs have been replacing EXPECT_STREQ,
there are still remaining things. So, this CL cleans up the remaining things
as much as possible.

Bug: 950077
Change-Id: I54fd3ca0703f39e9e7c40267b1d5732be836139a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1616932
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Commit-Queue: Gyuyoung Kim <gyuyoung@igalia.com>
Cr-Commit-Position: refs/heads/master@{#661910}
7 files changed