Issue 1:
A common UI pattern is having a text field which grows vertically, adding more lines, as you type, up to a certain number of lines, after which the content scrolls.

Presently, we can have a growing TextField by making maxLines=null. However, then the TextField never stops growing. Otherwise, if we make, say, maxLines=6, then it will have 6 fixed lines, and will not grow.

Unfortunatelly, maxLines was a bad name. That should have been called simply "lines", since it fixes the number of lines, and is not a maximum. However, that cannot be changed anymore.

I will now suggest adding another parameter, called maxLineLimit, which lets the number of lines grow until that number and then no more. And while we're at that, I would also add the less important minLineLimit.

So, for example, if we make maxLines=null, minLineLimit=2, maxLineLimit=6, then the TextField starts with 2 lines, and, if necessary to fit the text, grows until 6 lines. After that it scrolls.

This change is very easy to do, in file editable.dart, the method _preferredHeight in class RenderEditable has these last 2 lines:

_layoutText(width);
return math.max(preferredLineHeight, _textPainter.height);

These could be simply changed to:

_layoutText(width);
return math.min(preferredLineHeight * maxLineLimit, math.max(preferredLineHeight * minLineLimit, _textPainter.height));

Issue 2:
Steps to Reproduce

I have a flutter app which using cached_network_image to display image and using video_player to display video. The image and video display correctly when debug in simulator on a MacBook Pro which set a system proxy to access foreign http resources, as I'm in China! But when build a release ipa and install on my iPhone which have a VPN to proxy foreign http resources, the image and video can't be displayed. I can browse these resources in Chrome app.

Logs

[✓] Flutter (Channel beta, v0.7.3, on Mac OS X 10.13.6 17G65, locale zh-Hans-CN)
• Flutter version 0.7.3 at /Users/jagger/flutter
• Framework revision 3b309bda07 (13 days ago), 2018-08-28 12:39:24 -0700
• Engine revision af42b6dc95
• Dart version 2.1.0-dev.1.0.flutter-ccb16f7282

[✓] Android toolchain - develop for Android devices (Android SDK 27.0.3)
• Android SDK at /Users/jagger/Library/Android/sdk
• Android NDK location not configured (optional; useful for native profiling support)
• Platform android-27, build-tools 27.0.3
• ANDROID_HOME = /Users/jagger/Library/Android/sdk
• Java binary at: /Applications/Android Studio.app/Contents/jre/jdk/Contents/Home/bin/java
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)
• All Android licenses accepted.

[✓] iOS toolchain - develop for iOS devices (Xcode 9.4.1)
• Xcode at /Applications/Xcode.app/Contents/Developer
• Xcode 9.4.1, Build version 9F2000
• ios-deploy 1.9.2
• CocoaPods version 1.5.3

[✓] Android Studio (version 3.1)
• Android Studio at /Applications/Android Studio.app/Contents
• Flutter plugin version 27.1.1
• Dart plugin version 173.4700
• Java version OpenJDK Runtime Environment (build 1.8.0_152-release-1024-b01)

[✓] VS Code (version 1.27.1)
• VS Code at /Applications/Visual Studio Code.app/Contents
• Flutter extension version 2.18.0

[!] Connected devices
! No devices available

! Doctor found issues in 1 category.