Revert "CHECKs to debug why LocalFrame is in an inconsistent detached state."

This reverts commit 2b2acd1c.

Reason for revert: Root cause has been determined.

Original change's description:
> CHECKs to debug why LocalFrame is in an inconsistent detached state.
>
> A number of Android crashes have a non-detached LocalFrame but GetPage()
> returns null. This CL adds a few CHECKs in IsProvisional(), which is one
> place where this crash has been observed. It also adds a few CHECKs in
> the FrameLifecycle state machine to make sure state isn't somehow being
> rewound.
>
> Bug: 1154141
> Change-Id: I5b767ed3b7476a47a88831e40de1fceebb73e557
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2567633
> Commit-Queue: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: Fergal Daly <fergal@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#832617}

TBR=dcheng@chromium.org,fergal@chromium.org,chromium-scoped@luci-project-accounts.iam.gserviceaccount.com

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 1154141
Fixed: 1154583, 1154586, 1154676, 1154935
Change-Id: I53bc1544082baf6c91f99c18eb022f15c523ba5a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2575997Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Cr-Commit-Position: refs/heads/master@{#833968}

third_party/blink/renderer/core/frame/frame.h

@@ -398,12 +398,6 @@ class CORE_EXPORT Frame : public GarbageCollected<Frame> {
   bool ConsumeTransientUserActivationInFrameTree();
   void ClearUserActivationInFrameTree();
 
-  // Note: this is a temporary debug helper. Note that the despite the name,
-  // this is not the same thing as LocalFrame's FrameLifecycleState.
-  FrameLifecycle::State GetFrameLifecycle() const {
-    return lifecycle_.GetState();
-  }
-
   mutable FrameTree tree_node_;
 
   Member<Page> page_;

third_party/blink/renderer/core/frame/frame_lifecycle.cc

@@ -16,12 +16,12 @@ void FrameLifecycle::AdvanceTo(State state) {
     case kAttached:
     case kDetached:
       // Normally, only allow state to move forward.
-      CHECK_GT(state, state_);
+      DCHECK_GT(state, state_);
       break;
     case kDetaching:
       // We can go from Detaching to Detaching since the detach() method can be
       // re-entered.
-      CHECK_GE(state, state_);
+      DCHECK_GE(state, state_);
       break;
   }
   state_ = state;

third_party/blink/renderer/core/frame/local_frame.cc

@@ -34,7 +34,6 @@
 #include <memory>
 #include <utility>
 
-#include "base/debug/crash_logging.h"
 #include "base/metrics/histogram_functions.h"
 #include "base/unguessable_token.h"
 #include "mojo/public/cpp/bindings/self_owned_receiver.h"
@@ -2103,17 +2102,9 @@ void LocalFrame::ForceSynchronousDocumentInstall(
 }
 
 bool LocalFrame::IsProvisional() const {
-  SCOPED_CRASH_KEY_NUMBER("inconsistent-frame-state", lifecycle,
-                          static_cast<int>(GetFrameLifecycle()));
   // Calling this after the frame is marked as completely detached is a bug, as
   // this state can no longer be accurately calculated.
   CHECK(!IsDetached());
-  // TODO(https://crbug.com/1154141): This are added for temporary debugging.
-  // If a LocalFrame is attached, it should have both a LocalFrameClient and a
-  // Page associated with it. Yet there are some crash reports that seem to
-  // indicate that GetPage() is somehow null... confirm this.
-  CHECK(Client());
-  CHECK(GetPage());
 
   if (IsMainFrame()) {
     return GetPage()->MainFrame() != this;