Add explicit constructor and destructor to PDF accessibility structures

This changes adds explicit constructors to the following structures
- AccessibilityLinkInfo
- AccessibilityImageInfo
- AccessibilityHighlightInfo

It is done primarily to be consistent with AccessibilityTextFieldInfo
and to avoid code bloat because of implicit inline constructors.

Bug: 1015350
Change-Id: I548d01bec7b25f002985a4f07435cf624852279a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2275509
Commit-Queue: Virender Singh <virens@microsoft.com>
Reviewed-by: Ankit Kumar 🌪️ <ankk@microsoft.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#785651}

pdf/pdf_engine.h

@@ -273,6 +273,10 @@ class PDFEngine {
   };
 
   struct AccessibilityLinkInfo {
+    AccessibilityLinkInfo();
+    AccessibilityLinkInfo(const AccessibilityLinkInfo& that);
+    ~AccessibilityLinkInfo();
+
     std::string url;
     int start_char_index;
     int char_count;
@@ -280,11 +284,19 @@ class PDFEngine {
   };
 
   struct AccessibilityImageInfo {
+    AccessibilityImageInfo();
+    AccessibilityImageInfo(const AccessibilityImageInfo& that);
+    ~AccessibilityImageInfo();
+
     std::string alt_text;
     pp::FloatRect bounds;
   };
 
   struct AccessibilityHighlightInfo {
+    AccessibilityHighlightInfo();
+    AccessibilityHighlightInfo(const AccessibilityHighlightInfo& that);
+    ~AccessibilityHighlightInfo();
+
     int start_char_index = -1;
     int char_count;
     pp::FloatRect bounds;

pdf/pdfium/pdfium_engine.cc

@@ -409,6 +409,27 @@ void ShutdownSDK() {
     TearDownV8();
 }
 
+PDFEngine::AccessibilityLinkInfo::AccessibilityLinkInfo() = default;
+
+PDFEngine::AccessibilityLinkInfo::AccessibilityLinkInfo(
+    const AccessibilityLinkInfo& that) = default;
+
+PDFEngine::AccessibilityLinkInfo::~AccessibilityLinkInfo() = default;
+
+PDFEngine::AccessibilityImageInfo::AccessibilityImageInfo() = default;
+
+PDFEngine::AccessibilityImageInfo::AccessibilityImageInfo(
+    const AccessibilityImageInfo& that) = default;
+
+PDFEngine::AccessibilityImageInfo::~AccessibilityImageInfo() = default;
+
+PDFEngine::AccessibilityHighlightInfo::AccessibilityHighlightInfo() = default;
+
+PDFEngine::AccessibilityHighlightInfo::AccessibilityHighlightInfo(
+    const AccessibilityHighlightInfo& that) = default;
+
+PDFEngine::AccessibilityHighlightInfo::~AccessibilityHighlightInfo() = default;
+
 PDFEngine::AccessibilityTextFieldInfo::AccessibilityTextFieldInfo() = default;
 
 PDFEngine::AccessibilityTextFieldInfo::AccessibilityTextFieldInfo(