[headless] Allow print page ranges with range.to > page count.

Bug: 603559
Change-Id: Ib9316295cee0226fe19c966e47b0c5a6a730db44
Reviewed-on: https://chromium-review.googlesource.com/567504
Commit-Queue: Eric Seckler <eseckler@chromium.org>
Reviewed-by: Alex Clarke <alexclarke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#485914}

headless/lib/browser/headless_print_manager.cc

@@ -107,8 +107,10 @@ HeadlessPrintManager::PageRangeTextToPages(base::StringPiece page_range_text,
 
     if (range.from < 1 || range.from > range.to)
       return SYNTAX_ERROR;
-    if (range.to > pages_count)
+    if (range.from > pages_count)
       return LIMIT_ERROR;
+    if (range.to > pages_count)
+      range.to = pages_count;
 
     // Page numbers are 1-based in the dictionary.
     // Page numbers are 0-based for the print settings.

headless/lib/browser/headless_printing_unittest.cc

@@ -154,37 +154,51 @@ TEST(PageRangeTextToPagesTest, General) {
   std::vector<int> pages;
   std::vector<int> expected_pages;
 
+  // "-" is full range of pages.
   PM::PageRangeStatus status = PM::PageRangeTextToPages("-", 10, &pages);
   expected_pages = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
   EXPECT_EQ(expected_pages, pages);
   EXPECT_EQ(PM::PRINT_NO_ERROR, status);
 
+  // If no start page is specified, we start at first page.
   status = PM::PageRangeTextToPages("-5", 10, &pages);
   expected_pages = {0, 1, 2, 3, 4};
   EXPECT_EQ(expected_pages, pages);
   EXPECT_EQ(PM::PRINT_NO_ERROR, status);
 
+  // If no end page is specified, we end at last page.
   status = PM::PageRangeTextToPages("5-", 10, &pages);
   expected_pages = {4, 5, 6, 7, 8, 9};
   EXPECT_EQ(expected_pages, pages);
   EXPECT_EQ(PM::PRINT_NO_ERROR, status);
 
+  // Multiple ranges are separated by commas.
   status = PM::PageRangeTextToPages("1-3,9-10,4-6", 10, &pages);
   expected_pages = {0, 1, 2, 3, 4, 5, 8, 9};
   EXPECT_EQ(expected_pages, pages);
   EXPECT_EQ(PM::PRINT_NO_ERROR, status);
 
+  // White space is ignored.
   status = PM::PageRangeTextToPages("1- 3, 9-10,4 -6", 10, &pages);
   expected_pages = {0, 1, 2, 3, 4, 5, 8, 9};
   EXPECT_EQ(expected_pages, pages);
   EXPECT_EQ(PM::PRINT_NO_ERROR, status);
 
+  // End page beyond number of pages is supported and capped to number of pages.
+  status = PM::PageRangeTextToPages("1-10", 5, &pages);
+  expected_pages = {0, 1, 2, 3, 4};
+  EXPECT_EQ(expected_pages, pages);
+  EXPECT_EQ(PM::PRINT_NO_ERROR, status);
+
+  // Start page beyond number of pages results in error.
   status = PM::PageRangeTextToPages("1-3,9-10,4-6", 5, &pages);
   EXPECT_EQ(PM::LIMIT_ERROR, status);
 
+  // Invalid input results in error.
   status = PM::PageRangeTextToPages("abcd", 10, &pages);
   EXPECT_EQ(PM::SYNTAX_ERROR, status);
 
+  // Invalid input results in error.
   status = PM::PageRangeTextToPages("1-3,9-a10,4-6", 10, &pages);
   EXPECT_EQ(PM::SYNTAX_ERROR, status);
 }