Revert of r287982 Fix for race condition...

Revert of Fix for race condition where print preview hangs when attempting to print a PDF that hasn't loaded. (https://codereview.chromium.org/427723004/)

Reason for revert:
The changes fix an issue, but cause a more serious one. 

crbug.com/402402

Original issue's description:
> Fix for race condition where print preview hangs when attempting to print a PDF that hasn't loaded.
> 
> If |type| in RequestPrintPreview() equals PRINT_PREVIEW_USER_INITIATED_ENTIRE_FRAME and |is_loading_| is true, RequestPrintPreview() returns,
> then is called again, right after |is_loading_| is set to false in DidStopLoading(). 
> 
> 
> BUG=376969
> TEST=See bug for steps to reproduce.
> 
> Additional way to reproduce:
> Build blink_tests and browser_tests in out/Release. Then in src/webkit/tools/layout_tests run this command:
> ./run_webkit_tests.py --platform browser_test.linux source_pdf/
> 
> you can replace linux with win or mac depending on your platform.
> 
> The program will attempt to save a PDF as a PDF through print preview. It will eventually fail because Print Preview will hang due to this bug.
> If you want visual confirmation that this will happen open:
> src/third_party/WebKit/Tools/Scripts/webkitpy/layout_tests/port/browser_test_driver.py.
> 
> Then add this line of code to the function cmd_line.
> cmd.append('--enable-pixel-output-in-tests')
> 
> Then run the script again. Enabling pixel output will also make it significantly more likely for the bug to occur.
> Its also more likely to happen on windows for some reason.
> 
> This is how I came across the bug.
> 
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=287982

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=289181

[ivandavid, 2014-08-12 18:51:03]

Created Revert of Fix for race condition where print preview hangs when
attempting to print a PDF that hasn't loaded.

[commit-bot: I haz the power, 2014-08-12 18:53:24]

The CQ bit was unchecked by commit-bot@chromium.org

[Vitaly Buka (NO REVIEWS), 2014-08-12 19:10:26]

lgtm

https://codereview.chromium.org/463123004/diff/1/chrome/renderer/printing/pri...
File chrome/renderer/printing/print_web_view_helper.cc (left):

https://codereview.chromium.org/463123004/diff/1/chrome/renderer/printing/pri...
chrome/renderer/printing/print_web_view_helper.cc:1716:
base::Bind(&PrintWebViewHelper::ShowScriptedPrintPreview,
probably issue is some how related to these lines

[commit-bot: I haz the power, 2014-08-12 19:12:44]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ivandavid@chromium.org/463123004/1

[commit-bot: I haz the power, 2014-08-12 22:39:44]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel/...)

[commit-bot: I haz the power, 2014-08-13 00:11:53]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-08-13 00:11:56]

Try jobs failed on following builders:
  win_chromium_rel on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel/...)

[Vitaly Buka (NO REVIEWS), 2014-08-13 00:12:50]

The CQ bit was checked by vitalybuka@chromium.org

[commit-bot: I haz the power, 2014-08-13 00:18:21]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/ivandavid@chromium.org/463123004/1

[commit-bot: I haz the power, 2014-08-13 02:05:40]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  win_chromium_rel_swarming on tryserver.chromium.win
(http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[commit-bot: I haz the power, 2014-08-13 03:23:30]

Change committed as 289181