Rename GetMainFrame to GetPrimaryMainFrame

Progressively rename some usages of GetMainFrame to GetPrimaryMainFrame.

This is an automated change via emacs xref integration via codesearch
restricted to chrome/*

BUG=1250404

Change-Id: Ib5bcebf5e12631eb4823ac393921334b0b68f27a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3687769
Owners-Override: Dave Tapuska <[email protected]>
Reviewed-by: Nasko Oskov <[email protected]>
Commit-Queue: Dave Tapuska <[email protected]>
Cr-Commit-Position: refs/heads/main@{#1011128}
diff --git a/chrome/browser/iframe_browsertest.cc b/chrome/browser/iframe_browsertest.cc
index 6b0928ea..11b7ae6 100644
--- a/chrome/browser/iframe_browsertest.cc
+++ b/chrome/browser/iframe_browsertest.cc
@@ -59,15 +59,16 @@
   NavigateIframeToURL(tab, "test", file_input_url);
 
   // Invoke the file chooser and remove the iframe from the main document.
-  content::RenderFrameHost* frame = ChildFrameAt(tab->GetMainFrame(), 0);
+  content::RenderFrameHost* frame = ChildFrameAt(tab->GetPrimaryMainFrame(), 0);
   EXPECT_TRUE(frame);
-  EXPECT_EQ(frame->GetSiteInstance(), tab->GetMainFrame()->GetSiteInstance());
+  EXPECT_EQ(frame->GetSiteInstance(),
+            tab->GetPrimaryMainFrame()->GetSiteInstance());
   EXPECT_TRUE(
       ExecuteScript(frame, "document.getElementById('fileinput').click();"));
-  EXPECT_TRUE(ExecuteScript(tab->GetMainFrame(),
+  EXPECT_TRUE(ExecuteScript(tab->GetPrimaryMainFrame(),
                             "document.body.removeChild("
                             "document.querySelectorAll('iframe')[0])"));
-  ASSERT_EQ(nullptr, ChildFrameAt(tab->GetMainFrame(), 0));
+  ASSERT_EQ(nullptr, ChildFrameAt(tab->GetPrimaryMainFrame(), 0));
 
   // On ASan bots, this test should succeed without reporting use-after-free
   // condition.