Revert of Re-land: Enable XFA-Forms for the PDFium plugin. (patchset #1 id:1...

Revert of Re-land: Enable XFA-Forms for the PDFium plugin. (patchset #1 id:1 of https://codereview.chromium.org/1811743002/ )

Reason for revert:
Causing "Target image has run out of space" errors on Chrome OS builders:

http://crbug.com/595763

Original issue's description:
> Re-land: Enable XFA-Forms for the PDFium plugin.
>
> This reverts commit 13fe4645.
> See https://codereview.chromium.org/1761673002/
>
> TBR=thakis@chromium.org
>
> Committed: https://crrev.com/ed07b3773e3aad4a44a79a48c17162ef57ca82ee
> Cr-Commit-Position: refs/heads/master@{#381573}

TBR=thakis@chromium.org,ochang@chromium.org,jschuh@chromium.org,rpop@chromium.org,dsinclair@chromium.org,tsepez@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1814843003

Cr-Commit-Position: refs/heads/master@{#381764}

build/common.gypi

@@ -891,15 +891,11 @@
           'chromium_win_pch%': 1
         }],
 
-        # Whether PDF plugin is enabled, and which options it supports.
+        # Whether PDF plugin is enabled.
         ['OS=="android" or OS=="ios" or (embedded==1 and chromecast==0)', {
           'enable_pdf%': 0,
-          'pdf_enable_v8%': 0,
-          'pdf_enable_xfa%': 0,
         }, {
           'enable_pdf%': 1,
-          'pdf_enable_v8%': 1,
-          'pdf_enable_xfa%': 1,
         }],
 
         ['chromeos==1 or OS=="android" or OS=="ios" or desktop_linux==1', {
@@ -1230,8 +1226,6 @@
     'order_text_section%': '<(order_text_section)',
     'enable_extensions%': '<(enable_extensions)',
     'enable_pdf%': '<(enable_pdf)',
-    'pdf_enable_v8%': '<(pdf_enable_v8)',
-    'pdf_enable_xfa%': '<(pdf_enable_xfa)',
     'enable_plugin_installation%': '<(enable_plugin_installation)',
     'enable_plugins%': '<(enable_plugins)',
     'enable_session_service%': '<(enable_session_service)',