Revert "Make CapurePageText capture textContent only on dirty layout"

This reverts commit 802df057.

Reason for revert: suspected for causing memory regressions crbug.com/828026 and crbug.com/828027

Original change's description:
> Make CapurePageText capture textContent only on dirty layout
> 
> This is a partial revert for r536969 Change TranslateHelper to use a
> TextContent-like text dump.
> 
> r536969 is a workaround for a lifecycle violation bug that layout is
> still dirty after running layout update.
> 
> It turns out that textContent is not a good text dump for
> TranslateHelper, as pages may hide arbitrary content (e.g., JSON) in
> invisible text nodes, which can't be reliably filtered without checking
> element style or layout.
> 
> Since we don't always run CapturePageText() with dirty layout, there is
> no need to always dump textContent. Hence, this patch partially reverts
> r536969 that, we still dump innerText as long as layout is clean. We
> dump textContent only when layout is dirty, which is enough to get
> around the lifecycle violation bug.
> 
> Bug: 826174
> Change-Id: I63e97832caa9858e67992847fb9a22f6405183cb
> Reviewed-on: https://chromium-review.googlesource.com/984474
> Reviewed-by: Kent Tamura <tkent@chromium.org>
> Reviewed-by: Rachel Blum <groby@chromium.org>
> Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#547334}

TBR=groby@chromium.org,tkent@chromium.org,xiaochengh@chromium.org

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

Bug: 826174, 828026, 828027
Change-Id: I4c3200e5c7de0e6b3838ddcc40d53e751538f915
Reviewed-on: https://chromium-review.googlesource.com/992818Reviewed-by: Xiaocheng Hu <xiaochengh@chromium.org>
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#547796}

third_party/WebKit/Source/core/exported/WebFrameContentDumper.cpp

@@ -306,18 +306,9 @@ WebString WebFrameContentDumper::DeprecatedDumpFrameTreeAsText(
     size_t max_chars) {
   if (!frame)
     return WebString();
-  LocalFrame* local_frame = ToWebLocalFrameImpl(frame)->GetFrame();
-  // TODO(crbug.com/586241): We shoulndn't reach here with dirty layout as the
-  // function is called in DidMeaningfulLayout(); However, we still see this in
-  // the wild. As a workaround, we dump |textContent| instead when layout is
-  // dirty. We should always dump |innerText| when the bug is fixed.
-  bool needs_layout = local_frame->View()->NeedsLayout() ||
-                      local_frame->GetDocument()->NeedsLayoutTreeUpdate();
   StringBuilder text;
-  FrameContentAsPlainText(max_chars, local_frame,
-                          needs_layout ? TextDumpOption::kDumpTextContent
-                                       : TextDumpOption::kDumpInnerText,
-                          text);
+  FrameContentAsPlainText(max_chars, ToWebLocalFrameImpl(frame)->GetFrame(),
+                          TextDumpOption::kDumpTextContent, text);
   return text.ToString();
 }