Run clang-tidy modernize-use-equals-{delete,default} on //third_party/pdfium

See the bugs and cxx post for justification and details:
https://groups.google.com/a/chromium.org/forum/#!topic/cxx/RkOHzIK6Tq8

This change was done using clang-tidy as described here:
https://chromium.googlesource.com/chromium/src/+/lkcr/docs/clang_tidy.md

In some cases the the tool leaves behind a string of commas where it
replaced a member initializer list
(https://bugs.llvm.org/show_bug.cgi?id=35051). They were cleaned up
with:
  git diff --name-only | \
      xargs sed -E -i 's/(^\s*|\)\s*):[ ,]*= default/\1 = default/'

Bug: chromium:778959, chromium:778957
Change-Id: I23e60d3d6c8bc9e8574d425710a0441cb5510d6b
Reviewed-on: https://pdfium-review.googlesource.com/19970
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: dsinclair <dsinclair@chromium.org>

5 files changed, 7 insertions, 13 deletions

diff --git a/core/fxcrt/fx_coordinates.h b/core/fxcrt/fx_coordinates.h
index 0c0ccb065f..5840a14815 100644
--- a/core/fxcrt/fx_coordinates.h
+++ b/core/fxcrt/fx_coordinates.h
@@ -590,13 +590,7 @@ class CFX_Matrix {
   explicit CFX_Matrix(const float n[6])
       : a(n[0]), b(n[1]), c(n[2]), d(n[3]), e(n[4]), f(n[5]) {}
 
-  CFX_Matrix(const CFX_Matrix& other)
-      : a(other.a),
-        b(other.b),
-        c(other.c),
-        d(other.d),
-        e(other.e),
-        f(other.f) {}
+  CFX_Matrix(const CFX_Matrix& other) = default;
 
   CFX_Matrix(float a1, float b1, float c1, float d1, float e1, float f1)
       : a(a1), b(b1), c(c1), d(d1), e(e1), f(f1) {}
diff --git a/core/fxcrt/observable.h b/core/fxcrt/observable.h
index 659f8ad5b9..2013b75be9 100644
--- a/core/fxcrt/observable.h
+++ b/core/fxcrt/observable.h
@@ -55,7 +55,7 @@ class Observable {
     T* m_pObservable;
   };
 
-  Observable() {}
+  Observable() = default;
   Observable(const Observable& that) = delete;
   ~Observable() { NotifyObservedPtrs(); }
   void AddObservedPtr(ObservedPtr* pObservedPtr) {
diff --git a/core/fxcrt/retain_ptr.h b/core/fxcrt/retain_ptr.h
index 481bfbba56..e14b1ef5dc 100644
--- a/core/fxcrt/retain_ptr.h
+++ b/core/fxcrt/retain_ptr.h
@@ -28,7 +28,7 @@ class RetainPtr {
       m_pObj->Retain();
   }
 
-  RetainPtr() {}
+  RetainPtr() = default;
   RetainPtr(const RetainPtr& that) : RetainPtr(that.Get()) {}
   RetainPtr(RetainPtr&& that) noexcept { Swap(that); }
 
@@ -89,7 +89,7 @@ class Retainable {
   bool HasOneRef() const { return m_nRefCount == 1; }
 
  protected:
-  virtual ~Retainable() {}
+  virtual ~Retainable() = default;
 
  private:
   template <typename U>
diff --git a/core/fxcrt/unowned_ptr.h b/core/fxcrt/unowned_ptr.h
index 012af3ddf7..f9753cde37 100644
--- a/core/fxcrt/unowned_ptr.h
+++ b/core/fxcrt/unowned_ptr.h
@@ -39,7 +39,7 @@ namespace fxcrt {
 template <class T>
 class UnownedPtr {
  public:
-  UnownedPtr() {}
+  UnownedPtr() = default;
   UnownedPtr(const UnownedPtr& that) : UnownedPtr(that.Get()) {}
 
   template <typename U>
diff --git a/core/fxcrt/weak_ptr.h b/core/fxcrt/weak_ptr.h
index eb8523bd3d..3ec3942c5f 100644
--- a/core/fxcrt/weak_ptr.h
+++ b/core/fxcrt/weak_ptr.h
@@ -19,7 +19,7 @@ namespace fxcrt {
 template <class T, class D = std::default_delete<T>>
 class WeakPtr {
  public:
-  WeakPtr() {}
+  WeakPtr() = default;
   WeakPtr(const WeakPtr& that) : m_pHandle(that.m_pHandle) {}
   WeakPtr(WeakPtr&& that) noexcept { Swap(that); }
   explicit WeakPtr(std::unique_ptr<T, D> pObj)
@@ -76,7 +76,7 @@ class WeakPtr {
     bool HasOneRef() const { return m_nCount == 1; }
 
    private:
-    ~Handle() {}
+    ~Handle() = default;
 
     intptr_t m_nCount;
     std::unique_ptr<T, D> m_pObj;