Revert of PDF: Add some CHECKS to help debug a crash. (patchset #2 id:20001 of...

Revert of PDF: Add some CHECKS to help debug a crash. (patchset #2 id:20001 of https://codereview.chromium.org/457873003/)

Reason for revert:
No longer needed.

Original issue's description:
> PDF: Add some CHECKS to help debug a crash.
>
> BUG=402035
>
> Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=289822

TBR=gene@chromium.org
NOTREECHECKS=true
NOTRY=true
BUG=402035

Review URL: https://codereview.chromium.org/607743005

Cr-Commit-Position: refs/heads/master@{#297067}

pdf/pdfium/pdfium_engine.cc

@@ -2046,8 +2046,6 @@ std::string PDFiumEngine::GetPageAsJSON(int index) {
   if (index < 0 || static_cast<size_t>(index) > pages_.size() - 1)
     return "{}";
 
-  // TODO(thestig) Remove after debugging http://crbug.com/402035
-  CHECK(pages_[index]);
   scoped_ptr<base::Value> node(
       pages_[index]->GetAccessibleContentAsValue(current_rotation_));
   std::string page_json;
@@ -2105,8 +2103,6 @@ void PDFiumEngine::AppendBlankPages(int num_pages) {
         page_rect.height() * kPointsPerInch / kPixelsPerInch;
     FPDFPage_New(doc_, i, width_in_points, height_in_points);
     pages_.push_back(new PDFiumPage(this, i, page_rect, true));
-    // TODO(thestig) Remove after debugging http://crbug.com/402035
-    CHECK(pages_.back());
   }
 
   CalculateVisiblePages();
@@ -2274,8 +2270,6 @@ void PDFiumEngine::LoadPageInfo(bool reload) {
       pages_[i]->set_rect(page_rect);
     } else {
       pages_.push_back(new PDFiumPage(this, i, page_rect, doc_complete));
-      // TODO(thestig) Remove after debugging http://crbug.com/402035
-      CHECK(pages_.back());
     }
   }