Mac: Hack around Sierra autolayout bug in the certificate viewer.

chrome/browser/ui/certificate_viewer_mac.mm

Index: chrome/browser/ui/certificate_viewer_mac.mm
diff --git a/chrome/browser/ui/certificate_viewer_mac.mm b/chrome/browser/ui/certificate_viewer_mac.mm
index 93dd9c2c91598b5b31e85855632c83042b44fe2f..bed695be3f4044c54dc74dcca4d7f773e7127736 100644
--- a/chrome/browser/ui/certificate_viewer_mac.mm
+++ b/chrome/browser/ui/certificate_viewer_mac.mm
@@ -4,13 +4,76 @@
 
 #import "chrome/browser/ui/certificate_viewer_mac.h"
 
+#import <objc/runtime.h>
+
 #include "base/mac/foundation_util.h"
+#include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
 #import "base/mac/scoped_nsobject.h"
 #include "content/public/browser/web_contents.h"
 #include "net/cert/x509_certificate.h"
 #include "net/cert/x509_util_mac.h"
 
+namespace {
+
+// The maximum height of the certificate panel. Imposed whenever Sierra's buggy
+// autolayout algorithm tries to change it. Doesn't affect user resizes.
+const CGFloat kMaxPanelSetFrameHeight = 400;
+
+// Pointer to the real implementation of -[SFCertificatePanel setFrame:..]. This
+// is cached so a correct lookup is performed before we add the override.
+IMP g_real_certificate_panel_setframe = nullptr;
+
+// Provide a workaround for a buggy autolayout algorithm in macOS Sierra when
+// running Chrome linked against the 10.10 SDK on macOS 10.12.
+// See http://crbug.com/643123 for more details.
+// Note it's not possible to inherit from SFCertificatePanel without triggering
+// *** Assertion failure in -[BrowserCrApplication
+// _commonBeginModalSessionForWindow:relativeToWindow:modalDelegate:
+// didEndSelector:contextInfo:], .../AppKit.subproj/NSApplication.m:4077
+// After that assertion, the sheet simply refuses to continue loading.
+// It's also not possible to swizzle the -setFrame: method because
+// SFCertificatePanel doesn't define it. Attempting to swizzle that would
+// replace the implementation on NSWindow and constrain all dialogs.
+// So, provide a regular C method and append it to the SFCertificatePanel
+// implementation using the objc runtime.
+// TODO(tapted): Remove all of this when Chrome's SDK target gets bumped.
+id SFCertificatePanelSetFrameOverride(id self,
+                                      SEL _cmd,
+                                      NSRect frame,
+                                      BOOL display,
+                                      BOOL animate) {
+  if (frame.size.height > kMaxPanelSetFrameHeight)
+    frame.size.height = kMaxPanelSetFrameHeight;
+
+  DCHECK(g_real_certificate_panel_setframe);
+  return g_real_certificate_panel_setframe(self, _cmd, frame, display, animate);
+}
+
+void MaybeConstrainPanelSizeForSierraBug() {
+#if defined(MAC_OS_X_VERSION_10_11) && \
+    MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_11
+  // This is known not to be required when linking against the 10.11 SDK. Early
+  // exit in that case but assume anything earlier is broken.
+  return;
+#endif
+
+  // It's also not required when running on El Capitan or earlier.
+  if (base::mac::IsAtMostOS10_11() || g_real_certificate_panel_setframe)
+    return;
+
+  const SEL kSetFrame = @selector(setFrame:display:animate:);
+  Method real_method =
+      class_getInstanceMethod([SFCertificatePanel class], kSetFrame);
+  const char* type_encoding = method_getTypeEncoding(real_method);
+  g_real_certificate_panel_setframe = method_getImplementation(real_method);
+  DCHECK(g_real_certificate_panel_setframe);
+  IMP method = reinterpret_cast<IMP>(&SFCertificatePanelSetFrameOverride);
+  class_addMethod([SFCertificatePanel class], kSetFrame, method, type_encoding);

[Mark Mentovai, 2016/09/21 12:30:16]

Check the return value, at least via a DCHECK. This call will fail if
SFCertificatePanel already has an implementation of this selector. Apple might
even add it.

[tapted, 2016/09/21 13:07:04]

Done.

+}
+
+}  // namespace
+
 @interface SFCertificatePanel (SystemPrivate)
 // A system-private interface that dismisses a panel whose sheet was started by
 // -beginSheetForWindow:
@@ -88,6 +151,8 @@
 }
 
 - (void)showCertificateSheet:(NSWindow*)window {
+  MaybeConstrainPanelSizeForSierraBug();
+
   [panel_ beginSheetForWindow:window
                 modalDelegate:self
                didEndSelector:@selector(sheetDidEnd:returnCode:context:)