Make PDFiumRange moveable

Add an explicit move ctor to PDFiumRange, and use it in
PDFiumEngine::AddFindResult() to avoid copying. Also add move/copy
operator= to match the move/copy ctors.

Change-Id: Ia912938101120fb0027a50defcb5d3dd34fa6306
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5888525
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Alan Screen <awscreen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1359998}

pdf/pdfium/pdfium_engine.cc

@@ -1805,6 +1805,8 @@ void PDFiumEngine::StartFind(const std::u16string& text, bool case_sensitive) {
   bool first_search = (current_find_text_ != text);
   int character_to_start_searching_from = 0;
   if (first_search) {
+    // Do not move `selection_` here, as StopFind() expects to start with the
+    // existing selection.
     std::vector<PDFiumRange> old_selection = selection_;
     StopFind();
     current_find_text_ = text;
@@ -1906,7 +1908,7 @@ void PDFiumEngine::SearchUsingPDFium(const std::u16string& term,
       break;
     }
 
-    AddFindResult(result);
+    AddFindResult(std::move(result));
   }
 
   FPDFText_FindClose(find);
@@ -2044,7 +2046,7 @@ void PDFiumEngine::SearchUsingICU(const std::u16string& term,
   }
 }
 
-void PDFiumEngine::AddFindResult(const PDFiumRange& result) {
+void PDFiumEngine::AddFindResult(PDFiumRange result) {
   // Figure out where to insert the new location, since we could have
   // started searching midway and now we wrapped.
   size_t result_index;
@@ -2057,7 +2059,7 @@ void PDFiumEngine::AddFindResult(const PDFiumRange& result) {
       break;
     }
   }
-  find_results_.insert(find_results_.begin() + result_index, result);
+  find_results_.insert(find_results_.begin() + result_index, std::move(result));
   UpdateTickMarks();
   client_->NotifyNumberOfFindResultsChanged(find_results_.size(), false);
 }

pdf/pdfium/pdfium_engine.h

@@ -602,7 +602,7 @@ class PDFiumEngine : public DocumentLoader::Client, public IFSDK_PAUSE {
   void ContinueFind(bool case_sensitive);
 
   // Inserts a find result into `find_results_`, which is sorted.
-  void AddFindResult(const PDFiumRange& result);
+  void AddFindResult(PDFiumRange result);
 
   // Search a page using PDFium's methods.  Doesn't work with unicode.  This
   // function is just kept arount in case PDFium code is fixed.

pdf/pdfium/pdfium_range.cc

@@ -47,7 +47,13 @@ PDFiumRange::PDFiumRange(PDFiumPage* page, int char_index, int char_count)
 #endif
 }
 
-PDFiumRange::PDFiumRange(const PDFiumRange& that) = default;
+PDFiumRange::PDFiumRange(const PDFiumRange&) = default;
+
+PDFiumRange& PDFiumRange::operator=(const PDFiumRange&) = default;
+
+PDFiumRange::PDFiumRange(PDFiumRange&&) noexcept = default;
+
+PDFiumRange& PDFiumRange::operator=(PDFiumRange&&) noexcept = default;
 
 PDFiumRange::~PDFiumRange() = default;
 

pdf/pdfium/pdfium_range.h

@@ -28,7 +28,10 @@ bool IsIgnorableCharacter(char16_t c);
 class PDFiumRange {
  public:
   PDFiumRange(PDFiumPage* page, int char_index, int char_count);
-  PDFiumRange(const PDFiumRange& that);
+  PDFiumRange(const PDFiumRange&);
+  PDFiumRange& operator=(const PDFiumRange&);
+  PDFiumRange(PDFiumRange&&) noexcept;
+  PDFiumRange& operator=(PDFiumRange&&) noexcept;
   ~PDFiumRange();
 
   // Update how many characters are in the selection.  Could be negative if