PDF: Avoid doing work with empty rects.

Change-Id: I0d97bb34d9f04c4e2ece07d1f773c17f2ffb2c9f
Reviewed-on: https://chromium-review.googlesource.com/749678Reviewed-by: dsinclair <dsinclair@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#516045}

pdf/pdfium/pdfium_engine.cc

@@ -4004,6 +4004,9 @@ void PDFiumEngine::Form_OutputSelectedRect(FPDF_FORMFILLINFO* param,
   pp::Rect rect = engine->pages_[page_index]->PageToScreen(
       engine->GetVisibleRect().point(), engine->current_zoom_, left, top, right,
       bottom, engine->current_rotation_);
+  if (rect.IsEmpty())
+    return;
+
   engine->form_highlights_.push_back(rect);
 }
 

pdf/pdfium/pdfium_page.cc

@@ -501,10 +501,16 @@ void PDFiumPage::CalculateLinks() {
 
     int rect_count = FPDFLink_CountRects(links, i);
     for (int j = 0; j < rect_count; ++j) {
-      double left, top, right, bottom;
+      double left;
+      double top;
+      double right;
+      double bottom;
       FPDFLink_GetRect(links, i, j, &left, &top, &right, &bottom);
-      link.rects.push_back(
-          PageToScreen(pp::Point(), 1.0, left, top, right, bottom, 0));
+      pp::Rect rect =
+          PageToScreen(pp::Point(), 1.0, left, top, right, bottom, 0);
+      if (rect.IsEmpty())
+        continue;
+      link.rects.push_back(rect);
     }
     links_.push_back(link);
   }

pdf/pdfium/pdfium_range.cc

@@ -54,8 +54,11 @@ const std::vector<pp::Rect>& PDFiumRange::GetScreenRects(
     double right;
     double bottom;
     FPDFText_GetRect(page_->GetTextPage(), i, &left, &top, &right, &bottom);
-    cached_screen_rects_.push_back(
-        page_->PageToScreen(offset, zoom, left, top, right, bottom, rotation));
+    pp::Rect rect =
+        page_->PageToScreen(offset, zoom, left, top, right, bottom, rotation);
+    if (rect.IsEmpty())
+      continue;
+    cached_screen_rects_.push_back(rect);
   }
 
   return cached_screen_rects_;